I have a full size Aegis and totally love it , though I do hate the thumb safety that comes on them .
But with that being said for a carry gun I would get the CDP (in an ultra if that is the size you like) , I have a full size one for EDC.
If you are intending to do more range shooting than carrying it and just have to have a Ultra, I would suggest a Eclipse Ultra since it has a steel frame in place of the aluminum.
The extra weight will help tame the recoil some
I am like one of the posters above where as I only buy the full size models , but have a lot of friend swear by the Ultras.