mark_adders

Happy to.  The entire process was thoroughly explained in your previous thread.

In 2018

Yeah, the biggest difference is in the time to get your hands on a "Certified Copy" of the marriage certificate.  Usually fast in the US, but varies by state.  Ontario is notoriously slow.  Otherwise, no pros or cons really.  Remember to indicate you are coming for a visit, not coming to get married.  Both are true, but one will likely raise additional questions.

Either is fine
 
Marriage Certificate issuance in the US varies significantly

I believe this was answered in your previous thread.

Nothing illegal about getting married in the US, just leave after your visit. I got married in the US, returned to my home country a few days after the wedding and we started the CR1 process.
 
I was able to visit while my CR1 was processing, I had a stable job/life in the NL and only had short visits (1-2 weeks per visit) because of those strong ties to my home country. Never had issues visiting. 

Take all dates with a grain of salt.
When I applied for I-129f, the wait for petition approval was 6-9 months, when I was approved it was 12 months. I had no idea when I was going to be approved, each day I was looking at what cases they were processing trying to figure out even a rough idea, and there just was no possible way to estimate it. I didn't know things could change so fast, you never know with USCIS. 

I have a friend who applied for I-129f months ago when the speeds weren't exactly getting better, and their wait was an estimated 14-16 months. Now it's looking like it 12 or under, and they're not quite feeling ready for that speed. USCIS will throw countless curveballs at you, that will have you so confused. Hope for the best, expect the worst, and expect your expectations of the worst to be blown out of the water because somehow, they have the ability to always disappoint you.

USCIS timelines are simply a display of "How long have the current approvals been waiting?" not, "How will approvals look 12+ months down the line". In reality, you wont have a good idea on when you can/will move until you have the visa in your hand. There are even occasionally issues at the interview that lengthens your wait, Montreal for example gives out a lot of DS-3025 that ends up taking people like 6+ months to get through. Still uncommon, but point is; you don't know what will delay you. Don't rely on a timeline.

The thing that I think you're missing, is there are multiple steps to the K-1 process. First you file your I-129f petition, you wait for your case to be adjudicated either with an RFE, approval, or in rare cases a denial. Once approved, your case is sent to the national visa center which is essentially just a mailing center for K-1 (but they do a lot more for I-130 CR1/IR1) which sends it off to the consulate. Montreal then sends you P3, which is a pre-interview checklist to ensure you have everything you need. Once you reply to them with the information requested in the P3, they send you P4. That can be same day, or it can be a few weeks. P4 allows you to book the interview. My wait was about 5 months for the interview, and it would've been 4 but I had an issue with the consulate. They ghosted me, despite having only sent 2 emails. Weird. But we resent it on my Husbands end and got our P4.

As you can view from my timeline
My I-129f was approved in 367 days from my NOA1 date.
My interview took 521 days from my I-129F NOA1 date.

There wasn't a huge extra wait for my interview, and I still am a regular chatter with a bunch of other Montreal peeps whos timelines are very similar to mine, and more recent. 

I-130 is similar, but has a different NVC > Interview process which is longer than K-1's NVC > interview. For the I-130, they actually ask stuff for you at NVC and whatnot

I couldnt do I-130 because of covid, I couldn't leave Canada because there was a mandatory hotel quarantine that was costing people around $2000 at minimum in my area. I can't afford that, we had enough money for all visa expenses and the while of time I cannot work, but what we didn't have is "just because" money. We had no idea when Canada was going to lift those restrictions, so we filed K-1. The restrictions didn't lift until months later, so I am still confident in that choice but I do wish I-130 had been possible.

K-1 has sucked. If I leave out the part where they processed me as a b2 on entry, then it's still been a heap of trouble. 
Trying to get on my husbands bank as a joint sponsor, they kept trying to input me as a citizen. I kept telling them the importance of them NOT doing that, I'm not a citizen and I don't want false claims that I am literally being on my bank account, that sounds really dangerous. But time and time again they kept calling to check if citizenship was the right box, and said that they didn't have any other options because I don't have an ITIN. Eventually, they called some supervisor and was able to resolve that. When my husband and I were quoted health insurance, we searched all around. The cheapest we could find was like $250, with a 9k deductible and doctor visits not covered. I'm pretty young, so unless something absolutely devastating happens I am not frequenting hospital visits, nothing I do would even reach that 9k. We don't have that kind of money for a possibility. The only viable option, or the one I thought would be fine, was $500 and it had doctor visits, prescriptions, and I forget how much the deductible was but it was significantly less. 

The issue is, we don't have an extra $500/month to put towards health insurance! On a k-1 you can't work for awhile, so that's Rent/mortgage, health insurance, car insurance, food, and care products all on one persons pay. Many can afford that, some can't. It hasn't been an issue in my marriage, even now i'm not working to further my career despite being able to, but it is an additional stress for something that could feel very preventable if you were simply able to work! Not all jobs in america provides good health insurance either, my husbands work covers something so little that im surprised they can even call it health insurance. $150/year towards wellness checks, like.. $100 per overnight hospital visits...

Another big issue, is no travel permission. I have seen many cases of people who entered on a k-1, realize one of their close family members is dying. Even with an expedited I-131, they didn't get it in time to say goodbye. That's a real possibility, you never know what could happen and how fast USCIS will deal with it. There's something really hard about being the beneficiary, unable to travel knowing each day something could happen to your childhood dog, or your parent, or sibling, or friend, and not be certain that you'd be able to be there!

I feel so happy each day that I got my GC before anything bad happened, but not everyone is as lucky as I to be able to say that.

Hope this helps, K-1 is a nightmare and I hope that whatever path you choose, that it turns out great.

I was in the same boat, too.  My wife and I definitely wished that we could've done the spousal visa vs K1.  It was a loooooooong 1 year wait for her to get her green card.  She's working and happy now, about to take her driving test soon, too.  We're not looking forward to the long wait for the ROC.

If this lawyer was skewed toward the higher revenue generating option, then that lawyer would advise K-1. Literally a license to print money. Sadly, the people who can least afford K-1 tend to be the ones who pursue it. Then they arrive in the U.S. to face crippling:
 
* higher U.S. cost of living
* health insurance
* I-485 package 
* I-751
* no way to work for a year
 
As well as  total dependence on the good graces of the petitioner. In the wrong hands, K-1 and K-2 are a licenses for trafficking humans. Your prospective lawyer might also be thinking about this.

That is my thinking, too.  Adjustment of Status provides a great "continued employment" opportunity. 

You will learn very quickly that nothing makes much sense when it comes to US immigration.

There is nothing easy, cheap or quick about immigrating here. If you accept those facts now, you won't be disappointed. It is what it is.

@Crazy Catoutlined each visa.  K1s used to be quicker, much quicker.  Only certain circumstances warrant a K1 visa.  I believe the better option is CR1.  Yes, it may be a little longer, but much cheaper and less time involved.  I was K1, and would have rather opted for CR1....  just my two cents...

Personal (wife's) journey took 13 months for CR-1 in 2016-2017.  I have witnessed thousands of case experiences here since I joined Visa Journey in 2016.  I have seen many, many people regret they chose a K-1.  I have seen zero spousal visa couples who say they should have chosen a K-1 instead.  To me, that alone, speaks loudly.  

For your consideration:
 
K-1 
  More expensive than CR-1
  Requires Adjustment of Status after marriage (expensive and requires a lot of paperwork)
  Spouse can not leave the US until she/he receives approved Advance Parole (approx 6-8 months) 
  Spouse can not work until she/he receives EAD (approx 6-8 months) 
  Some people have had problems with driver licenses, Social Security cards, leases, bank account during this period 
  Spouse will not receive Green Card for many months after Adjustment of Status is filed.
  A K-1 might be a better choice when 18-21 year old children are immigrating also
  In some situations, marriage can affect certain Home country benefits, making a K-1 a better choice 
  A denied K-1 is sent back to USCIS to expire
  K-1 entrant cannot file for citizenship until after having Green Card for 3 years.
  Once an I-129F has been approved, delaying the case is difficult to impossible if the need arises.

CR-1/IR-1
  Less expensive than K-1 
  No Adjustment of Status(I-485, I-131, I-765) required. 
  Spouse can immediately travel outside the US 
  Spouse is authorized to work immediately upon arrival. 
  Spouse receives Social Security Card and Green Card within 2 or 3 weeks after entering the US 
  Opening a bank account, getting a driver's license, etc. are very easily accomplished with GC, SS card, and passport.
  Spouse has legal permanent Resident status IMMEDIATELY upon entry to US.
  The clock for citizenship filing starts immediately upon entry to the US.
  A CR-1/IR-1 case can be delayed indefinitely at NVC if the need arises.