I haven't watched any of the dubbed Black/White yet, watched bits and pieces of the first episode of it, but only did that so I could hear how Iris's voice in english sounds. And to be honest, I don't mind it, actually not mind I do like it.
1)What little I've heard of Iris' dub voice sounds okay to me. It's not as squeaky as the JP voice, which is a good thing since English dubs can't really pull off the super-high-pitched voices as well as Japan can.
2)This is really more of a non-spoilers matter by now, so I'm moving this to the general PAD forum(...after making sure that any spoilers in the posts here are marked, although VA discussion doesn't lend itself to much spoiler talk!)
I'm still a bit undecided. I got used to the Japanese voice already, so I'll have to get used to this one as well. She sounds a tad weird on certain phrases, but most of the time I actually enjoyed the voice.
Hopefully I continue enjoying the voice throughout the series. So far it isn't bad.