Agreed about the art transitions. Although it didn't stop me from watching FMA: B, it always bothered me a bit. Perhaps I'm biased because I watched FMA first, but I just liked the black outline and overall designs better. Actually, I liked most things from the fist FMA anime better than FMA: B aside from story.
I preferred Brotherhoods art over FMA, probably cause i read the manga and the art in Brotherhood was closer to the manga. FMA does have good dub, though i watched it both dubbed and subbed, if i was to watch it now i'd probably watch it dubbed.