Scorpion motors are very big in the larger aircraft scene. Good power, excellent efficiency, and excellent price. Plus, they have some special in the magnets which make the motor almost bullet proof to damage from getting too hot.
I got a SC4020-12 in my .50 size Kyosho FW190 and its AWESOME.
Wattflyer scorpion thread
RCgroups scorpion thread
The US distributor of scorpion motors gets on there a couple of times a week to answer questions etc.
Photos of the scorpion office/factory in HK
hope that helps :D
-Sid