ok, here's my honest answer.
if you even have to question whether or not this girl is worth staying with, she's not. there shouldn't be a doubt in your mind that she's worth it. if you wonder, then she's not worth it. so i'd break up with her and date the other girl.
or here's another solution.
every couple has their good days and bad days. everytime my girlfriend and I play putt-putt we have an awesome time. so here's my suggestion. plan an amazing day with your current girlfriend. go do some stuff she wants, and do some stuff you want. don't get in any fights with her.
now do the same thing with this second girl. a couple days later.
take an honest look at which day was more satisfying, and make your choice based on that.