I love the Budapest and use it as my main defense against 1. d4 in OTB now. It has two main advantages:
1. Even fairly strong players don't usually know it;
2. It opens the position early, which is the opposite of what most d4 players want.
In CC it's not as good; if you follow databases, White gets a bit of a edge in almost all lines. But that's generally true in most responses to d4 anyway.