I just finished the game maybe an hour or 2 ago and I thought it was a lot of fun. One of the best Pokémon games I've played yet. Nice story, I like the Aether Foundation, I thought Lusamine was an evil antagonist but it looks as it, it was partially due to the Ultra Beast influence on her as to WHY she did what she did in the game. Lillie was actually a really good character, I didn't think I'd like her as much as I did. As far as games go, I'd say she's my favorite female character, in general I'd say a close 2nd (Maybe 3rd). I like that she was actually a travel buddy for you after defeating the Aether Foundation (I also thought her possible crusish dialogue was amusing, there were actually a couple of moments where I thought she was going to kiss me XD)!!!. I made the best in-game team I've ever had in Sun and Moon
Decidueye (Leaf Blade, Shadow Ball, Synthesis, Steel Wing)
Serena/Sylveon (Moonblast, Swift, Reflect, Psyshock)
Fiarrow/Talonflame (Flamethrower, Acrobatics, Flame Charge, Steel Wing)
Greninja/Ash-Greninja (Water Shuriken, Aerial Ace, Extrasensory, Night Slash)
Metagross (Meteor Mash, Brick Break, Psychic, Flash Cannon)
Kommo-O (Sky Uppercut, Dragon Claw, Shadow Claw, Flash Cannon)
Somethings I didn't like were: Pokémon "Calling for help" which prevented me from catching one unless I KO'd the other, I would've preferred to see new characters instead of recycling 3 Kahunas as members of the Elite Four. Alola could've had a better Pokedex and more Pokémon from their region in general. Usually when I play a Pokémon game, I want my team to consist either entirely or mostly of Pokémon of that region and with the exception of Gen 2 and 7 I've been able to do just that. When I played Crystal and HeartGold I had only 1 or 2 Johto Region Pokémon be apart of my ingame team, while in Moon I only had 2 (Granted their good mons, but still). Introducing only 79 Pokémon? Most of which didn't even have great designs or typing. The Alola forms weren't anything special, still annoyed that ONLY Kanto Pokémon got Alola Forms when other Pokémon could've used a buff up. I thought the ending was the best I've seen so far, Lillie leaving.....that actually made me feel sad on the inside and those last two pictures of her and Lunala and the picture she takes with you and Hau on Meleme Island just gave me feels. Overall good game.
I still haven't played Gen 5 or 6. I technically haven't played Gen 4 yet either, I have HeartGold but I won't consider myself having played Gen 4 until I play D/P/or Pt. So far out of each generation I have played I'd say:
(Gen 4 based on HG) > Gen 3 >=< Gen 7 > Gen 2 >> Gen 1