Oh man isnt this just a can of worms to be released. :p
Anyway my brief answer to this is that it depends on the series. Anime like Cowboy Bebop, Comic Party, FMA, pokemon, Panty and Stocking with Garterbelt can be viewed as anime that succeeded as good dubs in my opinion. As for there are others that had the subs done a lot better. Dont think I can be more specific than this.
I like both since i watch both. But i like different sub and dub for different anime's
Subs: Kuroshitsuji, Soul Eater, Kore wa Zombie desu ka, etc
Dubs: School Rumble, Lucky Star, Soul Eater, etc
^^ The Ending
onething i didnt like is how they changed a bit of parco Fulgoire in Zatch Bell! they changed the song from being about boobs, to dancing all day.
Subs are generally better, but some dubs are great:
Studio Ghibli films
Yu Yu Hakusho
Some Dubs are funny/ ridiculously lousy:
Speed Racer Original (Ultrafast talking anyone?)
Ahhh logy ehhh aahhh. Speed RA er. Lolol. That was drawn by stan Lee.
If the dun is done well it's great~! Other then that though Subs are awesome~!
Speed Racer is Mach GO GO GO in Japan so no, not a Stan Lee drawing
I like dubs cuz it annoying to have to read the subs and I like English voices better it's funnier. Though on some occasions I guess subs are better but I like dub
im a dub person im kinda a slow reader so i spend more time looking at the bottom of the screen then whats going on. =/
the sub is better 9 times out of 10. but i really loved death note and trinity blood in english. this is one of the only things i'm really animu purist about