If you mean "best" in terms of popular villager, then I've had Diana, Fauna, and Tia, and Wolfgang. Tia was the only villager that I regret passing off though because my town was full at the time
So far, Fauna.. I wasn't actively looking for her but she was so adorable I invited her in. She is such a sweetheart ahh so glad she turned up in my camp! Second best would be Merengue, mostly because she is the most popular villager i've seen in the campsite aha.
Well, I've gotten and taken in Erik, Stitches, Beau, Bruce, Marshal, Rudy. My favorite was Erik, but now I think it's Stitches. Missed out on Freya, but I got her now, so it's fine.
I got Olivia in my tent once, but my town was full at the time. I also got Merry in my tent, and got her to move in. In my second town I found Marshal in my tent and got him to move in.
Now that I think about it I had terrible luck with my campsite. o:<
Normally I would just get these ugly worthless villagers.
The only "good" ones I ever got were Cookie and Julian and when they came my town was full o:<
Long story short, my campsite hates me.
I had gotten Francine once, but apparently my town was too full so she couldnt move in. I just cried forever. It still pains me cuz shes one of my dreamies (but I think I'd prefer Ankh over Francine).