Okay, here goes:
1. Snap on keypad is big but very light. It will go right into my laptop case for me to use when I'm on the road to send emails and SMS. It does not add much weight nor does it upset the balance of the 6315 when you put it on. When you put it on, you get a sound to let you know it's docked correctly, and to take it off, you just press on the two buttons on either side of the keypad and slide it right off. It is much better than the Treo 600's keyboard, which I'm coming from.
2. Screen is fine, doesn't wash out for me at all, and I'm here in the Texas sun

I haven't loaded any mpegs yet, maybe this weekend, and I'll let you know the results.
3. I cannot figure out how to make a call using Voice Command without touching the 6315. I've re-mapped the rightmost key (Inbox) for Voice Command, so I only have to press that, then after that everything else can be done from the headset.
4. I'll try and post some pics in a while; trying to finish up my workday right now!
Rob