Being in the Dallas area is irrelevant. K-1 approval times have nothing to do with geographical area in the US.
As reported by other VJ members, the average K-1 is taking about 350 days, while a CR-1 is taking, on average per VJ members about 595 days. As you are living together, I assume you have considered both the Fiance visa and the spousal visa. There is also the possibility of a direct filing with the consulate (DCF) for married couples with exceptional circumstances.
Every couple has their own priorities, and each couple must decide which visa is better for their situation.
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 3-6 months)
Spouse can not work until she/he receives EAD (approx 3-6 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.