The plot: two ex-special forces veterans take a group of rich playboys looking for adventure into the middle of an island's civil war.
At first, Soldiers of Fortune is a fun B movie that seems inspired by Verohoeven's campy, violent classics of the 80s. Like others have said, it quickly drops the camp and satire in favor of cheesy, low budget action sequences. I didn't really mind. If you're a fan of low budget action movies, it's likely that you've seen much worse. And you usually don't get such a great cast, either. Most of the actors are wasted, but it's always fun to see some good actors having fun, even if it's in a bad movie.
If you're looking for something that makes logical sense, has a good plot, and big budget special effects, I think you'll just hate this movie. On the other hand, if you enjoy inexplicable scenes that serve no purpose, a video game called Baby Killer ("I'm on the final level -- the maternity ward!"), and an arms dealer who refers to himself in third person as "The Grim Reaper"... maybe you'll find this amusing. There's enough silliness and camp to satisfy fans of B movies and enough action to keep you awake. However, it's never going to be anyone's favorite movie. Unless maybe you happen to be Christian Slater.