Once again, different strokes. What you consider usable, is not what another considers to be the same.
The Omnia works fine out of the box for many, but certainly not everyone. As for Exchange support, I think that there are some fairly large disagreements there. Without Mobile Me, you have no Exchange support. In fact, when Mobile Me first came out and for a while, it was a joke. I am sure it is better now.
My wife deplores touchscreen phones. In her opinion, if you want real usability, get yourself a smart phone that is non-touch. Everyone has different needs, abilities, and desires. There is no blanket statement for what is best, and what is most usable. As for games...once again, different strokes. I think people playing games on any device in public looks unprofessional, and silly, so meh.
Back to what I originally said, what are you trying to accomplish here? You no longer use an Omnia, but an iPhone. Plenty of iPhone forums out there, why choose this one to debate? Is there a point to the debate? You have already made up your mind. Are you simply trying to divert people from getting or using an Omnia? I really don't understand. I came from an LG Dare, and the Omnia smacks it around. But I have not once gone to an LG Dare forum to express my feelings or gloat about it.
