Personally, I prefer Peanut - I like her design better, plus I've had her in my town before and really enjoyed having her
Plus, she was always one of my favourites in Wild World, so I like her for nostalgic reasons too
Peanut, because it's peanut. Jk. Peanut, because I love her color scheme and she reminds me of such a cute but also shy cheerleader that is really sweet and not mean.
Also, I really don't like the bottom eyelashes/mascara Mint has going on. >_>
It would probably be Mint if it weren't for that minor design detail.
I was going to pick Mint because I enjoy her aesthetic more, but I realised apart from that I didn't really enjoy her as much when I had her in my old town. I had Peanut in the same town and I enjoyed having her around very much but I eventually moved her out in place of another public work project. I was very hesitant to, but eventually I did. So my vote goes to Peanut, also I love her catchphrase.