With air nailers it seems pretty hit or miss to me. A company like Bostitch will make some great guns, and some pretty terrible ones too. You really have to do your research on each model number and make sure you're getting the right one.
I have a Bostitch framing gun, model LPF33PT, and the thing is an absolute tank. Never jams and works great. But then I bought a cheap Bostitch branded 6 gallon compressor at Lowe's that was on sale and came with a Bostitch branded Brad nailer in the box. Didn't need the nailer so sold it cheap to a friend, and he said it's terrible. Jams all the time, he took it back and they replaced it once for him, and the second gun jams just as much.
Seems like it's a cheap gun that Bostitch just put their name on to give away with the compressor, but why do that? Just cheapens the brand.
I have a Ridgid brad nailer model R213BNF that I bought off recommendations and reviews, and it's awesome. Oil free model, never jams, doesn't leave big dents or out-dings in the trim. And it was cheaper than a lot of the bigger brands in air nailers.
On the other hand though, some Ridgid nailers aren't that great. So like I said, really hit or miss with specific products. So be weary of that.