The Sienna SE I test drove was not bad. It took corners ok for a boat with surprisingly little body roll, but I detected some under steer and there was no denying it was still a 4500lb boat.
The SE still had some merits above the LE, leather bolstered sport fabric seats, power liftgate, and it looks really good with 1/2" lower suspension, body kit, sporty lights, and 19" wheels. It probably drives better than the other minivans out there, but don't expect it to put a smile in your face the way a Mazda 5 would. At least it didn't for me.