The only Newtilda I've seen is Brooklyn Shuck and I was very impressed with her. She has a very strong voice that really stuck out to me. Her acting is a little stiff at times, but it was only her third show or so when I saw her and I'm sure she'll settle in more as she continues to go on.
Alison Luff, though, is an incredible Miss Honey. She's more animated than Lauren and Jill were, which works. She's charming and sweet, and her voice is killer. Really a wonderful addition to the cast.