The Willcom D4 looks like a great little UMPC. What represents the biggest news in the D4 is that it is a UMPC, not a MID (like the Nokia tablets). Any new MID is going to be a little behind the Nokia tablets because of the time they (and we) have put into the Maemo platform since the 770.

The biggest liability of the D4 is definitely the OS, although I've read there is an XP option in Japan, which would presumably be a big improvement, in that XP has a ton of available software, including downloadable software. The second biggest is the hard drive speed, IMO. The battery life is reported to be 3.5 to 4 hours, which is not bad for the size of the device. I'm no fan of Windows on a tiny screen, but the trade-off in OSs is that every smart phone benefits from/needs a computer to sync with. Combined w/ an iPhone or Windows XP smartphone, this is the smallest complete package for travelling. Even if you carry around a Nokia tablet and a smartphone, somewhere back there there's a computer.

I'm interested to see more Atom (or Isaiah) UMPCs. After seeing the 770 abandoned, I'm not eager to get into another MID for now.