at first i fly with a OS.46 AX and the UCD fly very good, a have unlimited vertical, and the better is the low weight, can land and take of on about 10 feet, can fly like a butterfly very slow and very light.......
With the .90 change something the stile of fly,,, is more ballistic need more to land, not to take of, you can fly slow but not like the .46......... i change the engine because i´m learning hover and with .46 can do it, but if i do something wrong, i dont have the power to go away on a second, with the .90 i´m feel someting is wrong , put full engine and an half of second wwwooooopp,,,,, go up.

i think the 2 stile are good,,,, only you know what do you want...

Sergio