We're only a family of 3 but only use studios and I love the kitchenettes for breakfasts. They're much better than a regular hotel room. We have tried them all and I definitely have my opinions about each of them.
While OKW may have 2 beds I didn't care for the actual room layout. There is a lot of floor space but the kitchenette counter area was small & most annoying to me was that the bathroom is all in 1 room there so if someone is in there nobody else can do anything about getting ready. We prefer to have the vanity sink area outside of the toilet & shower. It's just more efficient. And heaven forbid that DH gets in there first!

Nobody else will want to go in for half an hour!

We did not care for how spread out the resort is and the walk up to the main pool
can be a pretty good schlep depending on where you are put for your stay.
We like AKV to save points sometimes (and it is beautiful) but we prefer Jambo House over Kidani as far as AKV goes. We tried a value size unit once for 3 nights and I couldn't wait to get out of it. It is noticeably smaller - DO NOT DO A VALUE SIZE FOR 4 PEOPLE FOR THAT LONG!! One of my peeves about Kidani goes back to the bathroom layout and the kitchenette. At Kidani the toilet has its own room but the sink area is combined with the shower. Kinda weird. Still not our preferred layout. Also, the kitchenette area in Kidani is REALLLLY small and the microwave is miniature size and sink is not the usual "bar sink" size but is a small bowl shaped basin - it's difficult to even wash out the coffee pot. One final note about AKV regardless of which building you are in - there are a TON, I mean a TON of large pillows all over the sofa and the bed and you have to PUT them somewhere at night. We end up stacking them in corners and shoving them under the bed...but I find them annoying to deal with when you come in late at night and all you want to do is to fall into bed. Finally, we like being able to go to the Mara (counter service) at Jambo. It is one of the best CS places onsite and is not so convenient to get to from Kidani.
We really liked our studio at VWL. It was pretty spacious and the kitchenette countertop space was ample (probably at least a foot wider than most units). It also had 2 large closets which was really nice to be able to put stuff away - I don't think any other studios have 2 closets. It has our preferred bathroom layout too with the vanity area outside of the toilet & shower. If you can get into VWL you would like it there. Close to MK...peaceful...woodsy.
We stayed in a BLT studio last spring break for its proximity to the MK and the monorail...nice location but SMALL unit. Was glad we were only 3 and only there for 6 nights. The bathroom is small, it is all in 1 room and there is very little vanity storage area. The kitchenette area there tho is AMAZING. VERY big and lots of countertop and storage. If you plan on doing any meal prep in the room this could be a consideration over space. But you really have to like each other a lot and share a bathroom well. OH, and the pool at BLT is a joke. It is really small and has very little personal space. We ended up walking over to the Contemporary and using that pool as it was soooo much nicer. Plenty of space and lots of chairs.
BCV has the best pool and the studios are nice. BCV is tied for first place for us with VWL for our 2 favorites. The studios are of ample size and have our preferred layout plus there's the walk to the back entrance of Epcot and the pool. BCV is a win-win for us.
Our home resort is SSR and we like it just fine. The room had plenty space and the layout is good...we tend to visit DTD more when we stay there as it's so convenient. We have not tried the Treehouses yet as we never take a car but you may like one of those one day. I don't really have any big gripes about SSR. We like the Grandstand area there.
We also liked BWV just fine when we tried it last summer. We liked being able to walk to Epcot but when we went it was August but we had storms EVERY afternoon and they shut the boats down as long as there is thunder and lightening so that was sort of a pain. We liked the pool / slide and being so close to the boardwalk. Dining options were good on the boardwalk but basically non-existent at the pool. But the studio itself was good.
Outside of the WDW resorts we have also tried Vero and HHI - both of those resorts have enormous studios that are the best layouts and sizes available. But of course those don't apply to you in this case. We will be trying out VGC and Aulani this summer - can't wait to compare them to all the others!! As far as the studios at WDW we like BCV and VWL best then probably SSR. We like different resorts for different reasons.