Having stayed in both we prefer the longhouses for the bathroom layouts and style.
The longhouse has a bathroom with a tub, which one of our kids prefer. We also prefer the longhouse dedicated shower.
The longhouse studios are warmer with more red, orange, and brown, and the tower studios are cooler with more blues, greens, and off white. It's a personal preference but we fell in love with the original
DVC rooms so it's hard to shake.
They nailed the tower studio layout, other than bathroom size. The tower has so much storage all over from the bedroom drawers (no fifth sleeper means more storage) to the bathroom (prefer the shelf space). The kitchenette is fantastic avd has real cups, utensils, and plates, and a dishwasher). I really liked the sitting area and built in table. Theres a stand perfect for a suitcase for those living out of a suitcase, and plenty of underbed room to store away luggage. The longhouse storage is so haphazard because of the fifth sleeper, and it's a mishmash under the bed and in bathroom, and overall longhouse storage is weird.
The tower garden terraces are great but only one faces the MK. That said, l prefer the one facing rest of the Poly resort. We did not try for fireworks but with only one facing MK I suspect it gets crowded.
The tower bar at Wailulu is fantastic and is the best non-Trader Sam's/Tiki Terrace bar at Poly. I like it better than Tambu Lounge and the pool bars, which are pretty good on their own so it's high praise from me to Wailulu.
I think it's fair to call tower transportation a huge weak point. Getting to/from EPCOT is a straight mess. You're either walking all way to TTC (far) or you're taking MK monorail to 4th stop and transferring at TTC. The longhouse advantage to TTC is huge, and this also plays out at park close when monorail are a mess and ferry is easier. A last thing on transportation, even the GF Poly boat is slow. The boat goes MK-GF-Poly-MK. As a test I got off boat at GF and my wife stayed on to Poly. I beatbher back to the room by 5 minutes and I'm a slow walker. It shows both how slow the boat is and how close to VGF building the Poly tower is.
The tower is great to expand room options but in future if needing a studio with our kids we will choose a longhouse version next time. We have a duo booked to save points without kids, but if we needed a one or two bedroom we'd first want another resort because the location *with the high
point chart* is bested by other resorts.