Well, I just saw The Expendibles. It's a decent action movie, lots of explosions and a few funny jokes here and there, but it has a lot of faults.
First the story. It's completely forgetable to the point that there's a good chance is all that you'll remember is that there was a 20 minute gunfight in between 4-5 minutes of dialouge. Don't go in expecting an Inception grade story. That's all I can say.

As for the special effects, it ain't no Avatar, I can tell you that much. I'm not saying I could do better, but they are amatuer in most parts. It has an action movies standard explosions and blown up bodies. But for things like buildings falling and a certain scene where someone caught on fire (not gonna say who =P), it was really obvious that computer cg was used to create the effect.
Overall, it's a good action flick where you can shut off your brain and enjoy the explosions and gunshots.
If I had to rate it, I'd give it a 7/10