Not sure what kind of phone you use now. But if you have a WM Device now with touch screen capability download the Diamond keyboards to your existing phone and play with them. This is what I did because I had the Mogul and was really wondering if I could live without the keyboard.
For me, I am tired of carrying around a brick. I had the PPC-6700 before the Mogul and they are both Bricks. Great phones mind you, in fact the 6700 I liked better, but I just can't keep having this brick on my hip.
I ultimately wanted to blend my Phone, Laptop and iPod together in one unit. Biggest complaint I will have on the new Diamond is no upgradeable memory
but its a trade off...will only move my top albums to the Diamond and keep the iPod for travel.
Good luck with your choice.