yeah that was my take on the battery life as well. As I mentioned the 12" display and the digitize yet still getting about 4hrs with a very small battery, I recall the battery is only one-cell it might be three but honestly I do not remember clearly and am too lazy to look as I am posting from the, ahem, "reading room".
Personally I like the device. It is the closest to meet my needs as a reader and a tool to increase my workflow. I've always used laptops but anymore they are just too awkward to my needs today so I have been hunting a slate device for a few years now. Until this Eee Slate I haven't found any of the tablet PC's particularly attractive as I want a reader AND medium-light duty general computing device. This Eee Slate really seems to address those needs. The price is about $300 more than I had hoped to spend but that won't influence my decision as I do have a moderatly pressing need.
I love that with this you can run all the reader software and all my work related apps save Lightroom 3.x which can hit your hardware far harder than even Photoshop if you use the adjustment tools. I might be able to run it to do simple work on images but I would eventually need to finish them on a more powerful PC. Still that is OK.
I just wish they had shoehorned a larger battery into it. but space is a premium and there will hopefully be a new version in short order. So we'll see.