>>54096098JN has better bigger eps I'd say, and the nostalgic returns are nice. The downside is Ash's JN team really didn't get much screentime outside of battles, and I feel that hurts them a lot. Hell even the Unova pokemon outside of the extra captures get better characterisation.
SM had better world building, recurring cast than BW as a longshot. The slice of life stuff I could take or leave, but it was unique for the show. I think as a cast I like the Alola cast more than the others. I actually think in terms of the actual battles this season might be weaker than the others besides a few though?
BW has a really solid first half as long as you ignore Trip and how Ash acts during Elesa which drags it down. If Ash's Unova team continued to evolve I would have been perfectly fine with it as a whole. It really feels like a fast paced version of the older seasons just with better battles. But BW does go to hell with the Unova league onward, and that really tarnishes it as a whole.
Cilan is fine, Iris is good to fine, I probably prefer them over Go and Koharu I guess.