Sounds like you haven't tried any of the decent ROM's on XDA... Otherwise you'd simply look at the Omnia and laugh. (The Resolution alone should be a killer for anyone considering it - My Phone 2 years ago had the same resolution screen!)
Alot of the Touch Pro ROM's are bad, many don't even have half-decent 3D Drivers. So please flash a decent one, try out some of the many useful Touch Pro Specific Utilities.
Sorry if I sound too biased against the Touch Pro, but personally I think its a brilliant phone and to me the Omnia is equal to the TyTN 2 that my Touch Pro just replaced.
I used a lot of cooked ROMs on both phones, but there are still a lot of issues on the HTC like GPS is s*** no matter what I try or Contacts are dissapearing when I connect the phone to a computer without WMDC/AS
And resolution is only one thing... Smaller resolution + faster CPU means: even faster phone (and there is the T-omnia if you want 800x480). And the 3D drivers the ROM builders put into their phones are from the omnia (which has good 3D capabilities but unfortunatley only D3D and not OGLES)...