
Here's what I think, Dungeons & Dragons supplements are only good if everyone in the group is using them, aware of them and agree to use of them otherwise it looks like you're try to hack the game to get an edge over other characters. Yeah, in the core my character can do this but according to the supplement he can do more!
I've played with a lot of Dungeon Masters that like to add in their own homebrew stuff and I'm OK with it so long as they tell me before and not use it like an excuse in the middle of something. Example, "Oh you would have hit but remember in my rules you don't have the bonus…." .