it just varries by series. I admit I used to be one of the people who always said subs were better, but I've watched a lot more anime since then. Some I liked in english (Burst Angel, Bubblegum Crisis (newest one), Love Hina, Full Metal Alchemist etc) and some were just more enjoyable in japanese (Azumanga Daioh, Evangelion, DNAngel, etc) It all depends on who they get to voice them and how close they stick to the original words without watering it down for "kids". It seems a lot of people in the US seem to think if its animated its automatically for children.
I recently saw Steamboy.. and having Patrick Stewart play the grandpa really annoyed me on many levels because I grew up watching Star Trek: The Next Generation with him as Capt Picard. There are other examples out there too but I can't think of any off the top of my head