I used to have the PPC-6700 w/ the slideout keyboard and really never used it. The device was bulky and certainly not a "pocket" pc. I usually used the stylus to do all my typing. Now that I have the Diamond, and have optimized my battery via registry edits and a few days of battery charging/utilization, my battery is working great! 4 bars for almost 16 hours, and I've done text msging, surfing the web for 15 minutes, voice calls totaling 30 minutes, weather updates, etc.
I thought I'd need external storage but 4gb is a lot for these devices. I do not intend on buying any songs from Sprint Music Store.
My Diamond has turned out to be a Best Friend.