The older ones were more expandable than the newer ones. From the reviews I have read on this one it appeared to be a converted Windows model of sorts. While it makes it expandable (there is a large panel on the bottom with access to 2 dimm slots and the hard drive) there are some trade-offs:
1) An older Celeron 847 that runs at 1.1ghz with no turbo option.
2) A fan is needed for the processor.
3) While the memory is upgradable it isn't low-voltage.
4) That battery life is average. With a full charge it lasts about 3 hours. A replacement battery may help here.
5) The hard drive - while spacious - isn't as fast as a SSD would be. Tempted to buy a cheap one to put in.
6) For Chrome OS a 320GB hard drive is overkill.
Newer Intel-based Chromebooks have much longer battery life and run much faster. However the memory and storage are soldered to the motherboard and can't be upgraded.
I've been using it since last Friday and so far I like it a lot. For browsing it works well enough, but on occasion browser tabs will crash. Adding memory helped in that regard.