Hmm the last time we booked a studio was when I was 15 or 16 and stayed in the room at SSR with my parents. It wasn't bad at all because we don't cook when we're on vacation, we're used to sharing two queen bed rooms during our vacations, and we spend a small amount of time in the room and most of the time in the parks. That being said, as a previous poster mentioned, space & being comfortable is all relative. I personally think it wouldn't be a big deal, but I definitely agree in making sure you all have your own personal space. It's great if your room comes with a balcony because that's another nook to just get out of each other's way. We also try to use all the facilities in the resort we're staying at when we're sharing a small hotel room- such as the community hall, lobby, and pool.
As previous posters mentioned, the sofa bed isn't hard to deal with at all and it's nice to have the space when you do end up folding up the sofa bed. This is a really embarrassing note to add, but I am so bad at folding up those beds! hahaha I got good last year when I shared the sofa bed in a 1 bedroom in the concierge level of Jambo House with my best friend. However, I'll be by myself on the sofa bed this upcoming trip in a 1 bedroom in BWV. Hopefully I'll get it after day 3 haha.