I owned a couple UMPC devices in the past (Samsung Q1 and Fujitsu U810), but then decided to stick with a MSI Wind netbook for my mobile computing needs. James has me actually considering a new slate ultra-portable computer though with his extensive posts on the upcoming Viliv S5 device. This computer is quite compact and has some great specs such as the 1.33 GHz Intel Atom processor, 1GB RAM, 60GB hard drive, 4.8 inch 1024x600 resolution touch screen display, WiFi, Bluetooth, integrated GPS receiver, and Windows XP.
Viliv has an interesting Cube interface that serves as a quick launcher utility to quickly get to your loaded applications. James is seeing good battery life and performance on the device with very little compromising going on. Dynamism will be carrying the Viliv S5 and is holding a special presales event starting at 1300 Eastern time on Monday, 27 April. You can preorder it during this event for $599 that also includes a spare battery, car mounting kit, and leather pouch ($135 value). UMPCs that I purchased before started at $899 so I think $599 for this device is actually quite good and cheaper than many mobile phones that I purchase.