The queue is getting longer every day......but have you considered the CR-1?
Every couple has their own priorities, and each couple must decide which visa is better for their situation.
Slightly faster arrival in the US
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 5-6 months)
Spouse can not work until she/he receives EAD (approx 5-6 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 denied K-1 is sent back to USCIS to expire
Slightly slower arrival in the US
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.
Intent to deny can be rebutted and reviewed.