-wide field of vision
-limited to the amount you can tighten it
that's pretty much it
Not a bad mask for the money. I bought mine used for $20 and it's worked great for the games that I've played (mostly woods ball). Granted this is the only mask I've had so I don't have much to compare it to. I've noticed that on many of the higher end masks there's no clip and you have to slide the mask over your noggin. It's a bit more convenient to have a clip. The mask is pretty low profile and didn't stick out in unnecessary places. I've played full days in the woods and have had no problems with this mask fogging up, even if it did it's a minor thing that can be remedied easily. The only real problem I had with it was that I couldn't tighten it much more. With a mask I like to feel it secure and pretty much stuck to my face. This mask was fine but could've been a bit tighter. other than that, it's a good mask for the money.
Good mask, like I said, haven't worn others so I'll be sure to review against this one when I get a new mask, but for now this works great.