The biggest problem with homebrew is that most of it is unbalanced crap made up by people who think rule of cool is an appropriate substitute for learning why those numbers in that book they barely skimmed are arranged the way they are. Yes, there's some good stuff out there but like the internet in general Sturgeon's Law is usually a generous assessment.
A great example was in a game I briefly played the DM allowed a homebrew class with seven different class features, most of which could be used in the same turn combined to great effect, at first level. Why? Because the DM didn't know half the rules to the basic system, the class came from a pretty website that was designed to look like an official source book, and the abilities sounded really cool. Nevermind that it made one PC more powerful than the other four party members combined.
Take homebrew with a large grain of salt or everybody will end up very salty.