Omnia definately is more snappy than the diamond/tp, video playback is better, the screen is worst since it is only wqvga resolution, so there are a lot of apps that dont support it unfortunately, like the HTC apps wont work. But i love titanium and it works great on the omnia, no lag when sliding between panels, screen is large, video camera is definately better than diamond and pro, its pretty good for a phone. Never really used touch wiz since it just came with 6.5 when i bought it used.
Its more clear on the phone, photobucket likes to f**k the quality