We would not have gone to WDW at all when our 2 kids were younger if it wasn't for the one bedroom. DH would have put his foot down and nixed the trips!!!!!
The way we vacationed, we REALLY used the kitchen a lot during those young years. So, much easier to feed the baby first. We spent a lot of time in the room.
We did laundry each and every day. And it seemed that one or both of the kids would get sick if not EVERY trip, every other trip! The washer/dryer really came in handy when DD was sick in the middle of the night and I had to launder all the towels she got "sick" on.
5 years into
DVC and 9 trips under my belt, I have yet to stay in a studio because we love the larger units so much.
My girls (5 & 8 then) and I will be staying in a studio during our next trip. DH won't be going so I think we can go to a smaller unit. We will eat out more and spend less time in the room. But I will miss the washer/dryer in the room but the girls are are old enough that they can watch tv while I pop down to laundry room or better yet, they can help me carry!
That all being said, if you are wanting to stretch your points and you have never stayed at either, I would advise you to try the studio FIRST. Otherwise, if you are like us, it will be harder to downsize later.
Good luck vacation planning!!!!!