It just works!
Yeah, right... While I appreciate amazing battery life boost, installation itself was terrible. My issues with the whole process:
- Download size. Is it really neccessary to download 5GB? It seems that Apple still lives in the past and, instead of downloading only changed files and/or applying differences, it downloads everything and then just replaces folders. OS upgrade - 5GB, Xcode update - 2GB. And lets download it from superslow apple servers (I did his from India. Other downloads are reasonably fast, but downloads from App Store takes ages).
- Upgrade froze at "less than 1 minute remaining...". Luckily I read some threads about this bug happening to other people too during install, and that hard reboot helps. It did. Still got bad kind of butterflies in my stomach.
- After reboot Mac presented me with setup process exactly same as the first time I booted it up. Choose language, create account, etc. Oh my... did I just lost all my data? I couldn't choose my previous username and that gave me hope (btw, process how username is allowed/disallowed to enter is really user-unfriendly and got me confused for a while). Ok, everything is setup, now mandatory reboot and... Again step one of whole process? WTF??? And again I can't choose either my old username or newly created - so everything is kinda working. Don't see the option to skip this process and just login with my existing account. Oh well. Complete everything one more time and hope for the best. Yes... Got logged in straight to my new account. Logout, login with mine - everything works. Except I now have new wallpaper. Minor nuisance. Let's hope they fix it for the next release and apply new wallpaper only to new account or if old account has unchanged default wallpaper.
On the plus side (and the most visible change) is battery life. My last year's MacBook Air when just charged on average showed 11 hours. Now it shows ~15-17 hours. If I turn off wi-fi and dim screen and do only reading or listen to music (w/ earphones and lid closed), Mavericks squeezes out 20 hours.