My dad has it. It's the same as every other WiMo phone.
I have the HTC Touch Pro and my dad agrees with me that it's better, It has a proper qwerty keyboard and a nicer interface(once you remove the crappy Manilla themes providers install and use the proper HTC one anyway ;p)
The camera on the Omnia isn't that great either, the lens isn't great and reduces it's photo quality(may not be a problem for you if your not worried about it
)
Other things I can think of: Screens bigger on Omnia which is nice.
Like most things, depends what you're using it for/looking for.
Oh also, if you plan on using the internet on it make sure you get a data plan else you'll be wasting a fortune =p