Personally I like K-1. WHen I was legal assistant, I did more than 200 K-1 in 3 years with success rate over 95%. It is faster and you two can be together while waiting for green card with EAD.
Last K-1 I did took two interview total from I-129F to the date of 2nd interview takes 9 months and 3 weeks from China.
K-1 is not a immigrant visa. However you are allowed to adjust here in the states.
Good luck!