Wow, what a mouthful!
BMS is a derivative (I think) of Open Falcon. It is light years ahead of AF and better in every way that I can think of.
The graphics have been pushed to a higher DX level and are much improved over AF.
There are other theaters you can fly in that are at various levels of completion. The Israel theater is very close to complete and can be fought to completion...yes, it is winnable!
BMS is very stable in my experience. It supports multiplayer and there are servers with 24 hour force on force campaigns playing.
You can have AF and BMS installed concurrently, but I think once you fly BMS you will not find a reason to fly AF any longer. Honestly, the community has pretty much coalesced around BMS at this point.
Also, as a side note, the Mirage 2000 and A-10 are flyable in BMS with very nice 3D cockpits. You are still limited by the underlying F-16 avionics, but it is remarkable how different they feel nonetheless.
A few BMS shots:
Guam theater (not really complete yet)