In my opinion Stitches and Marty are the cutest ones out of those, but I'm gonna say Marty because Stitches is everywhere already and Marty is cuter + has the amiibo exclusivity factor if that's worth anything.
I've always had Stitches in my town so I can't help but love him love than the others. Marty looks adorable too, but I don't have his card so he isn't in any of my towns. Barold though, he's getting nothing but petty from me. I still remember when he plotted on my town and haunted me for several months before moving.
I currently have Chester, so I voted for him. I never liked him at first but now that I have him in game, he's grown on me.
I had Barold before, as a starter. I kept him for about 8 months, constantly avoiding him until I saw him speaking to Curt (lol). I would only recommend Barold if you've got Curt. They look like siblings of some sort and they have awesome conversations.
Pudge. Stitches is one of the starter villagers I have in Longborn, and while he is cute, I wouldn't be too upset if he moved out. I've been thinking about replacing him with Pudge, but haven't done it yet because I don't feel like tiling my town to get him to move into a good spot.