I've been waiting to upgrade to Mavericks for quite a while now from 10.6.8, and thought I'd leave some feedback. I did a clean install on an SSD from a USB stick, but won't have a recovery partition. Overall: Much smoother than I thought. I'm not seeing any of the weird hangs in Finder that others have mentioned. It generally feels quite snappy. Boot time is insanely fast - like 20seconds on my 840 evo. The weird issues I'm seeing so far: 1. Random beach balls probably every 10-15min. They disappear so fast that it doesn't really get in the way of my work, but it's odd. 2. No left/right swipe gestures in Finder is awful. I'm having trouble getting Better Touch Tool to work properly for it as well. 3. Double-tap for secondary click was slow and lagged, but was fixed by disabling smart zoom in preferences > trackpad > gestures. Basically the trackpad is waiting to see if a second tap is coming, which makes the menu delayed. If you don't use smart tap, definitely disable it - it feels SO much faster. 4. When trying to return from idle / screen blacked out, the touchpad sometimes won't wake the computer. Only using the keyboard will for some reason. 5. Some weirdness in finder: files sometimes use the wrong icons, particularly in context menus. Also, when using the context menu "Open With", it will wait to spin up my regular HDD for some reason. No idea why. I don't use Safari or Mail, so I can't really comment on those.