This thing looks pretty sweet to me. I've been extremely picky about choosing a PDA waiting for basically something like this. Supposedly it will be available at the end of this month on the carrier I currently have.
Things I don't like about some of the best phones/pdas I've seen:
Not a fan of Palm OS
I don't really want to carry two devices
I want to have GSM/GPRS AND Wi-Fi and bluetooth
Touchscreen/ NO KEYBOARD!
All these problems have been solved hopefully, and I may get myself a PDA and frequent this forum more often finally. I had been looking at the 4315, but I figured the dual device problem would be solved shortly. Wohoo!
I have a 5555 for work ,but I will be moving back to the US soon and am going to have to buy a phone. Currently considering the h6315, however, I don't think it's got the horsepower I need. I keep a ~300Mb Wikipedia database open in TomeRaider, Websters Unabridged in eReader, and various others in Microsoft Reader, all open at the same time. Downgrading from a 400Mhz to a 168Mhz processor is going to hurt.
I still might do it, just for the added benefit of not having to carry around two devices. It's a clincher tho :)