Sean, some guns will run just fine with a buffer in and some won't. That probably explains most of the opposing opinions you have heard. According to the guy that didn't have any problems they are GREAT, and the guy that had short stroke problems they are a product of the devil.
The other factor is durability, some guns chew them up pretty quickly, and some guns are pretty easy on them. Combine this with wide variations in quality of the buffer itself and it probably explains the rest of the opposing opinions. A guy with a gun that eats them up buy soft buffers and they are JUNK, where a guy with a gun that is easy on them gets a more durable buffer and he thinks they are great.
Pick some up, try them out. If they are to be used in a HD/CCW gun put them in at the range and take them out at the range until you are positive they don't affect function. This will also give you a chance to see what the durability is like in your gun.
I use them. I don't know that they have helped anything for certain, but the idea is sound and they sure haven't hurt anything.