Taking whole evo lines into account from gen 1 to 7:
Gen 1: Squirtle line is good from start to finish. Same for Bulbasaur. Charmander is okay, but I don't like Charmeleon/Charizard. (7/9)
Gen 2: Don't like Croconaw all that much, but Totodile and Feraligatr are good. Chikorita line is good from start to finish. Same for Cyndaquil. (8/9)
Gen 3: Solid all around for Hoenn. Don't dislike any stage and am quite fond of Swampert and bawk bawk supreme aka Blaziken. (9/9)
Gen 4: Piplup and Empoleon are good. Indifferent on Prinplup, but don't dislike it. Turtwig line is good from start to finish. Chimchar is okay, but I don't like Monferno/Infernape, with the latter probably being my least favorite fully evolved starter ever. (7/9)
Gen 5: Snivy line is good. I like Tepig/Emboar too. Indifferent on Pignite and the entire Oshawott line... but I don't dislike them. (9/9)
Gen 6: Fennekin line is my fav Fire type starter line. Chespin and Chesnaught are good, but I don't like Quilladin. Froakie/Frogadier I like, Greninja not so much... not enough to dislike it, but I'm not big on it. It's kinda meh. (8/9)
Gen 7: Rowlet and Decidueye are good, but I don't like Dartrix. I like Litten and Torracat, Popplio and Primarina. I dislike Brionne and Incineroar does not exist as far as I'm concerned. (6/9)
So... gen 3.