That resume well the strenght of engines.
Yep UT3 is big, but have lot of advanced graphic features could it be textures morphing shaders, clouds etc ...
Im' not sure you'll be able to create any game with it easyly ?
I hope to see some new thread about UT3 by you some day
What i don't like is the fees you pay per game once you reach enought money and all life as your game is sold.

That's why i avoid it and because im'm not sure to be able to make some enought big and next gen game needing UT3 !