I grew up with Gilmore Girls. It holds a very special place in my heart. I was in the same grade as Rory on the show, so as she aged, so did I, and I identified with the show quite a bit. I rewatched much of the show for the first time in years in the leadup to the Netflix movies, and...well....
Personally, none of Rory's boyfriends were any good for her IMO, but they were the type you'd expect her to date at those specific points in her life. Dean was very much in the mindset of the average teenage guy. He's a good guy but not emotionally mature. I'd say more but the OP is still on Season 3.
Jess.....ugh. Ughhhhhhhh. Lorelai sums it up nicely when she says to Luke "Rory is 17. I'd say it's about time for a Jess." That's pretty much bang-on. He's not totally bad, and he fulfills a specific role in her life. She's better for him than he is for her (which is also true of Logan, later on).
Logan....ugh again. And actually, I hate him the most out of the 3, because he totally ruins Rory as we know her. I don't want to say much because of spoilers, but again, she's better for him than he ever was for her. He fulfills a role in her life, but ultimately he's a bad influence on her and he makes her a selfish person. One can argue that "Goody-goody Rory" was gone by the end of season 4, but Logan ended that completely by the time he came around. God, I hated him. He got a little better in season 7 but still....ugh. My feelings about him haven't changed in the 9 years since I originally saw the episodes. I hated him then, and I hate him now.
And really, the events of "A Year in the Life" didn't really surprise me simply BECAUSE Logan changed Rory. People always said that he supported her dreams, blah blah...nah. He taught her to be selfish and snobby, not realistic and focused. She was always a girl that wrestled with the 2 worlds, rich & middle class, and Rory's path in the show has always been about the conflict between those worlds and the pains of growing up (aside from her relationship with her mom).
Logan changed her forever, and ultimately in a bad way in my opinion, even if ALL of her relationships were valuable life experience for her.
For what it's worth, I'm "Team Marty" (season 5). They ruined him when they brought him back in Season 7.