I kinda like it. Then again, I did buy the PRS-500 on it's release, so I figure I'm the target audience for this sort of thing.
I hate the fact that there isn't a standard DRM eBook format that's inter-operable between devices though. I already have about 20 books on Sony and moving to Amazon's Kindle would stop me from accessing them without rebuying.
Not sure it's really intended for net browsing. More for push content like newspapers, blogs, etc. $10/month for WSJ delivered straight to my EBook? $2/month for magazines? Not bad at all.
Admittedly, content is kinda sparse on that end.