John Siracusa’s Mavericks review is a full twenty four pages long. It’s well worth the read, if you want to know more about Mavericks than any of your friends.
His verdict?
All of this is a roundabout way of getting to the essential question of any OS review: should you upgrade? OS X is (still) not iOS. The upgrade risks are greater, and there is no easy iCloud-based backup and restore for your Mac to save you if things go awry. If you’re currently running Mountain Lion, is there anything in Mavericks that makes it a must-have upgrade?
If you’re using a Mac laptop, I’d say yes. A potentially multi-hour increase in battery life will likely improve the quality of your life as a Mac user far beyond the price—in terms of time, not money this year—of upgrading to Mavericks.
If you have a desktop Mac, I still recommend upgrading if any of the features that you’ve read about made you mentally exclaim, “Finally!” For me, there are several. Over the past three years, each successive release of OS X has found its way onto all of my Macs in less time than its predecessor. This year, I may have already gone Mavericks-only across my whole household by the time you read this. Barring any unforeseen bugs or compatibility issues, Mavericks seems like a no-brainer upgrade to me. But you can be sure I’ll have a fresh set of backups—and you should too.
So there you go. Mavericks is available for free on the Mac App Store.