z-moves are alright. don't really care much for them though and the animations for them were.... questionable, to say the least. i don't like how static the models looked while performing the Z-moves, it really ruined a lot of them for me.
dynamax/gigantamax i've enjoyed a lot more than z-moves, surprisingly enough! maybe it's because there's a sort of strategy to dynamaxing whereas Z-moves is just kind of a one-time nuke then and there. with dynamaxing i have to choose my moves very carefully as those three turns matter and can outright decide a match one way or another.
gotta agree with dakota above though in that megas were the most enjoyable for me. both on a practical level and on a design level. it's hard to argue against a mechanic that was given to under-utilised pokemon like absol, ampharos, mawile etc. such a shame Game Freak did away with it. .__.