I really hate dubs--as a rule. That said, this is probably the best dub I've ever seen (beats DIC anyday). That's not to say I don't hate it--I do, but it's got nothing to do with whether or not the dub is good. It's excellent! Couple things, though:
1) It's not just that Artemis' voice is deep, it's that he's all breathy. He honestly sounds like a porn star, sitting on Minako's shoulder and sticking his face in her neck. Even if the voice were deep, it might work if the actor just kinda chilled on the breathing.
2) Rei's voice was amazingly similar to Keiko's--but the acting was a itty-bit flat, especially when she was telling them to watch out, and...well, it's just personal preference, but the script threw me off. I just can't see Rei saying, "I'm really sorry to meddle." The really, the sorry, it's all too much. Maybe like, "I don't mean to meddle..."
Totally nitpicky.
3) This is also personal preference, but...what kind of accent does Ami have? It's not British again, is it? =_= Haha, I guess this isn't a criticism, more like a...WTF?
4) Also...the Ma KOE TOE!! was a little weird, but I guess it'd be weirder if they were saying Makoto in perfect Japanese, so--eh.
Good things:
1) Impeccable timing.
2) Jupiter! Perfection!
3) Is the music redone? Very ambitious! I like the original music, but the new music was done very professionally.
4) Good sound quality.
5) For the most part, excellent acting.