unreal engine 4 (it's not the UDK!) is in a similar price category as gamestudio now.
for the price of one gamestudio pro edition you can use the unreal engine for 4 years. (edit: seems you can even quit the 20$ per month subscription and continue using the current version you have - you just don't get updates anymore.)
a pretty tough competition between unreal and unity seems to be starting.
valve seems to go into a similar direction too with their upcoming new source engine.
(edit: seems you can even quit the 20$ per month subscription and continue using the current version you have - you just don't get updates anymore.)