When I got my D2 I haaaated it for like the first week. I was deadset on returning it. I came from the iPhone 3G. Then one day I decided to sit both devices next to each other and do a variety of tasks I would normally do (browse the web and send some emails w/ attachments, check email, make notes, check weather, etc.). The iPhone was connected via my home wireless. It was then that I realized I was just being a baby and was just dealing with the shellshock of a switch from a phone I used for two years. The D2 blew the iPhone 3G away with speed and with so much more you could do. Now I loooove the thing! I just want to say right off - the physical keyboard gets a LOT better in time. It truly needs breaking in. When you first get it it feels stiff and not very responsive. Use it for a while and it's like butter, works beautifully.
As for the screen, I love it! Small enough to not be a brick on my belt but still very high resolution. When using landscape I almost never need to zoom. Keep in mind a quick double tap does a "quick zoom" that enlarges the page a bit for better viewing. I find navigating the internet on it simple and easy, not sure what you meant by that. I can easily select a bookmark, go back, go forward, etc.
Anyhow, so yeah, at first I hated it and now I absolutely love it. You might want to at least give it a week or two to make a final decision.
Rev.