I've stayed in the treehouses and it was fun - they are definitely more disconnected though - it's a fair walk just to SSR - if boats are running it's easy to get to Disney Springs. Busses are not as fun - if you're reasonably close to Saratoga and don't mind the walk, you can walk over to the Grandstand or Springs stops - or you have to take an internal Treehouses bus over to Saratoga, then switch busses to get to a park.
I stayed in the Cabins at Wilderness one night as a guest visiting someone there - and loved it in every way. Never stayed at the bungalows, though they always looked cool - in general though, the cabins are more my style. They seem to have a little bit more privacy from the neighboring cabins - the bungalows I feel like they're just too close and look into each other's balcony space more. I love how 'dark' the cabins are - it's part of what I love so much about Wilderness Lodge - I'm in hot, humid Florida, but the design and decor make me feel like I'm in a timber lodge in the Northwest - the cabins somehow make me feel like it's cooler out just because of the design. And I love the Wilderness Lodge grounds and building. With the Contemporary boat service restored, there's even good access to more restaurants at Contemporary and all the Monorail resorts.
If choosing one to stay on my dollar, I'd go with the cabins at Wilderness Lodge, Poly Bungalows 2nd, then Treehouses.