I talked to the consular section chief at the DR consulate. He said that the K-1 way was the fastest by far. IF you go the Marriage visa route, your application goes through more steps in the US before even being sent to the DR. Then, they told me that for immigrant visas, there is a 7 month wait for appointments.

Interestingly, I was told that if you get a Dominican resident card (equal to our green card) then you can apply directly to the US INS office (NOT the consulate) in the Dominican Republic for a marriage green card for your spouse.

I sent in my Fiancé visa app May 23 and it was approved July 14 by Nebraska.