I also have an OS .91 in mine, and have Hitech 425BB's on the elevators and ailerons, 945 metal gear on the rudder. I really like the way the plane flies. I've got issues with knife edge tending to tuck toward the belly, but I think as my skills and time with the plane increase that shouldn't be an issue. It is really good hovering, but has a heck of alot of wing rock in harrier/elevator type maneuvers. You have to really be quick on the sticks to keep the wings level. Earlier discussions in this thread have indicated that others have had the same experience. The OS .91 is very good in this plane, but I wouldn't say mine "rockets" out of a hover. But, I'm only running 10% and also am using an extra head gasket to reduce preignition, which probably reduces power too. Even so, it will go vertical on takeoff until I can't see it anymore. All in all, I'd say it's definitely a keeper.