1. As reported by other VJ members, the average processing times are almost the same for a K-1 (510 days) vs a CR-1 (549 Days).
2. Do NOT have any ceremony before the official marriage inside the US (for a K-1) which could be seen as a marriage. Legally marry in the US first, then you can have a ceremony outside the US.
You might want to see this:
Every couple has their own priorities, and each couple must decide which visa is better for their situation.
K-1 (VJ average processing time 510 days)
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 (VJ average processing time (549 days)
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.