I just called last week for a studio for 6 nights for March 21-27. They had all six nights available for the Lagoon View and the Standard View. We would have had to waitlist for 2 of the six nights for the Magic Kingdom view (the Monday and Wednesday I believe), but the other 4 nights were available.
We chose not to stay there this trip, though, when I read about how small the studios are compared to the other resorts. Since it will be our first stay in a studio with all four of us (myself, DH, DD6, DD5), we decided to stay at BCV again (and no waitlisting was necessary there either).