Oh no I took too long to vote oh well lol
well, my vote would have easily gone to Samurott. I love its hidden ability Shell Armor and I just simply adore Oshawott with every fiber of my being
close contenders were Blastoise who is just overall a beast, Empoleon since it has one of the best dual typings in Water/Steel, and Greninja since I think frogs are cool.
I really just never use Feraligatr even though I don't think it's bad in the slightest, and I really like Totodile and Croconaw. It's just that the other two Gen 2 starters always call out to me more. Swampert I've definitely used and I think it's great (but I'm not that crazy about its Mega, lol)
Inteleon is the worst designed final stage water starter of all time imo it's an insult to my love of lizard-based Pokémon, but hey we were going to get a stinker at some point. It completes my unholy Triforce trifecta of most hated starters of each type: Cinderace for fire, Meowscarada for grass and Inteleon for water.
And Quaquaval unfortunately doesn't get a pass from me. I do like its movements in battle and its typing, but I just can't get behind that overall design. I can at least say that I don't quite hate it as much as Inteleon. It doesn't look as huggable and squeaky clean as Quaxly, but it also isn't as horrendous as Quaxwell.
Good on Primarina for winning! I think it's pretty great. The Water/Fairy typing is powerful.