Had the S3, S4, S5, Note 3, Note 4 and now Note 5. TouchWiz was always pretty heavy on top of android and always seemed to be the culprit in slowing down prior phones but that's not the case in my time with the Note 5. No issues here. As for the look of TouchWiz, it hasn't changed a lot, some but not a lot. Themes and or a launcher can change all that for you. The Note 5 runs great, so yes, IMO TouchWiz is much improved.