The most interesting feature of the new device is the ability to record using analog or digital connections directly to the device. My guess would be that people who smuggle cassette and DAT recorders into concerts will just love this thing.
It is black and has a four button pad (as well as a sophisticated remote) for controlling its actions.
Form factor looks like the iPod for the most part, but the Philips site provides only a width (19.9mm) and a weight (167g) to compare against the iPod. How does it compare? At 19.9mm, it's about 25% wider than the iPod's 15.75mm. And the HDD100 is a little heavier (less than 10%) when compared to the 159g of the iPod.
It'll be interesting to see some reviews of this device. By the way, no Firewire.