Well, I haven't stayed in a studio yet. I have either stayed in the 1 bedroom with 2 people or the 2 bedroom with 4 people. I have to agree with Richyams, I think the 2 bedroom is perfect for 4 people, I hate to keep pulling the couch out!
With that said, I don't know if I won't ever stay in a studio, next year we will only have 100 points left after our scheduled trips with the family and if I want to take a trip again with my best friend, it will either be a very short trip in a 1 bedroom or we will stay in the studio for more days. I think we might just choose the studio and see how it goes.