By all accounts, it seems a decent piece of kit. It certainly blows the direct competition out of the water.
The way I see it, it's basically a business phone (Exchange, ActiveSync, VPN support) that also has a huge appeal to consumers because it's the sexiest mobile ever made.
Depending on how it's sold, I can definitely see it replacing every Blackberry in the companies I work at. It's basically ideal for me in my job, because I'm often on the road and the always-on Internet would be a huge help.