Interesting replies in here :-)
Although I personally would say that UD will have trouble because of the science later on. Its huge.
TMs are also a nightmare for UDs.
However you guys are right that they have good sustainablity which is a huge plus. Especially compared to orc. However I still think that orcs can be utilized better.
@Persian yup, you are right about the avians that it burns you out. But in a active KD that utilize them well it would be awesome. And you dont need to go full Avians, you can always mix it with some other race.
I wouldnt say that UD is useless, but there are better choices imo and I understand people going with UD, just surprised that so many people went with them.
Still its nice to get other peoples POV. You can never stop learning new stuff about utopia.
Edit: Ofcourse i understand that in some setups UD would work better then Orc. Im just talking generally here. Not in a specific setup :) However we can still compare setup vs setup, but i don't think people would like to share that here ;-)