Yes I have been flying it. I have roughly 20 flights on it now. It flys very nice. One of the most stable planes I've flown. The HB 61 that i am using to power it with makes a lot of power surprisingly. Spinning the APC 13-4W prop at 11700 rpm. It makes over 8lbs of static thrust and the plane weights just over 6lbs with a full load of fuel. Unlimited vertical. It will hover at 1/2 throttle and it maintains a hover very easily. The only thing i'm alittle disappointed about is knife edge flight. It has serious roll and pitch coupling problems. Once I get that all mixed out, it should be much better. Inverted flat spins are very flat with min loss of altitude. Elevators and harrier flight is very good, little to no wing rock with about 30% spoilerons. Waterfalls are excellent and very tight. Snap rolls are about what you might expect from a fun fly type of plane. Rolls are quick and axial. The plane tracks very well thru up/down lines and loops both inside and outside. Landings are super smooth, but you have to be able to get a very low idle or the plane will just continue to float right on down the runway, especially once you get low on fuel and the cg starts creeping rearward. So far i'm pretty happy with it.
As far as sticking a 91fx on it, I'd love to know how that works out. The 61 bushing motor is plenty for all out 3d as it is. Plus it is very good on fuel also. A typical flight (15 minutes)with quite a few full throttle blasts to the moon only uses about half a tank. I think it is either a 10 or 12 oz tank.
goodluck!
Al