I'll give you my thoughts as we own two 3 bedroom units.
We purchased the first 3 bedroom unit at Ocean Pointe with the belief we would eventually need the space as the kids started having kids of their own. This need never materialized. Now it's extra room for our luggage or, we can lock it off and exchange the studio portion. While we've always been able to upgrade the studio to a 1 bedroom, we've had to do so with instant exchanges online. While it's been great, the rules behind exchanging are ALWAYS changing. Now I.I. has instituted a $99 upgrade fee per room if we want something more than a studio.......and we always want at least a 1 bedroom unit. Changes in exchange rules have impacted how we use this particular unit and many times it's just the 2 of us in a 3 bedroom when a 2 bedroom would be more than adequate. If I had it to do all over again, I'd probably go with the 2 bedroom unit at Ocean Pointe.
The other 3 bedroom unit is at Grand Chateau. We bought this larger unit for an entirely different reason. We can use the 2 bedroom master unit when we're in Vegas and this unit has one location, on the end cap of each hallway, which provides outstanding views. The lock-out unit is a full one bedroom and trades as a one bedroom. We've can do request or deposit first for other 1 bedroom units within the Marriott system and we've done well with it. If we had it to do all over again, I'd still buy the 3 bedroom unit at Grand Chateau.
So, if it were us, I would stick with the 2 bedroom unit, even if the 3 bedroom units purchase price were the same (I wouldn't want the extra MF's). But, we're in our 50's and we own 3 other timeshares so, we don't need a studio unit for exchange. Also, with I.I. now charging an upgrade fee, I really wouldn't want a studio unit to exchange as we prefer, at a minimum, a 1 bedroom unit.