Okay, Watched part of Episode 1 (I'll watch the rest later).
The actor choices seem a bit hit or miss. Aelita and Jeremy's are good, visual wise at least, and Williams for the little I've seen of him (If Jim were a bit bigger, it would have seemed like he jumped right out of the animation).
Their choice for Ulrich and Yumi are alright, they just seem a bit off. I mean, Melanie Tran and Quentin Merabet seem good for the roles, but the latter seems a bit older and the former seems to almost, but not quite fit (I don't know why, she just seems a bit, a very little bit, off to me. maybe it will change as I watch more.)
Gulliver Bevernaege as Odd is...sorta okay. He seems to have the right kind of attitude, but while he is 16, he looks a good deal younger and that works against him a bit in my eyes. He almost seems like he should be Odd's little brother or something. Other than that and the darker hair shade they could have lightened a bit when they added the purple streak, he seems alright.
Gotta roll, stuff to do.