I'm a big booster of JoliOS. It's really impressive how well it's put together. It has its shortcomings (namely, it doesn't handle being offline very well) but other than that it really is awesome.
I think most people can probably live with one of these OSes without a problem. I got in the habit of using Google Docs and Calendar more and ended up liking it because I didn't have to worry about the actual files moving place to place (obviously, any computer can do this and dropbox does move files easily).
When you consider a full-featured Jolibook is $289, it's pretty compelling for most peoples' basic computer needs, web browsing, and e-mail. Power users won't like it, but that's not the target demo anyway.
Current Apple Stuff: 24" iMac, iPhone 4, AppleTV (original), 4gb Shuffle, 64gb iPad 2.