I can answer #1 a little bit.
I haven't used the PDA to its full potential. If you're asking about battery life, it's very good. It's never gone below 66% for me, even if I a) haven't charged it for a week and b) have used it sporadically during that week.
The screen is easy to use and doesn't require much thinking to use; it's logical, if you will. I personally haven't used the Word or Excel parts of it, but my father has (it belongs to him, not I). He hasn't had any trouble entering data or phrases.
The only minor detail I don't like is its size -- it's kinda large for PDA. Along with this, the wireless antenna is an inch wide, half a centimeter tall, and as deep as the PDA -- so rather than a flush top, you've got this bulbous thing sticking out. The PDA case from Dell protects it, but still, it's kinda... un-flush looking.
That's about it for me.