They are good. I got my parents one at Christmas to get them online (PAYG sim) and they’ve enjoyed it and had no problems. I’d get one myself after using theirs a fair bit, if my netbook dies. But I quite like google, and its apps, docs, and mail.
Main thing to be aware of if you’re thinking of it as a “laptop” is that you won’t be able to put your own programs on it. It all runs in the chrome browser, using cloud storage and apps, not like windows with a sepperate browser. There’s loads of apps for everything needed but if you have a special program required, you can’t load it onto it. Its worth checking if there’s an app equivalent though, you’d be surprised. That’s pretty much the thinking behind the viruses being unable to be downloaded to it too.
True about the fast start up, but remember your restricted (but not completely pointless) in its use if you can’t get online for some reason. If you’re ever going to take it out the house (a good option ‘cos the battery lasts all day) then get the one with the 3G sim for sure.
edit
If you haven’t already, download and use Chrome as your browser for a while. Set up a google+ account, try google docs and gmail, and look at their apps store. You’ll get a good idea if the software suits you. Its all free.
The hardware is very good, but you need to be happy with the software too.