GPS is the main thing I see. Also it only runs Java apps, which AFAIK are scarce for serious productivity/communications roles, and long on games/calculators/etc. (Then again, that describes the state of iPhone, S60, etc. apps as well, so maybe not a real problem...)

Although QVGA is kinda tiny, that shouldn't be a huge issue, since S40 (and apps designed for it, e.g. Opera Mobile) fits nicely on much smaller screens. I do wonder what the web browser will be like.

Anyway, I could definitely see grabbing this (or rather a T-mo USA version of this) as a modem if my next handheld computer doesn't have a phone built in.