Mavericks is a huge improvement but it's clear that the GM still has a number of bugs and general fiddly bits.
A few I've noticed:
1. Elevation gesture in Maps is awkward, often bounces back instead of moving.
2. iBooks page change animations are too fast; looks absolutely horrible and makes it unusable for me. I'd like a continuous scrolling option, too (as on iOS).
3. Finder icon mode size could be adjusted by pinching in Lion. Disappeared in ML and still gone in MVKS. I'd like to see it come back, the tiny slider control is too fiddly.
4. Menu bar icons won't show their menus if you click one item then hover over the rest. You need to click each item individually to make it show its menu. You can just hover for the App's menus, though.
5. Need to keep entering AppleID information after update. First iCloud asked for my password, then I got email notifications about signing in to the account, then I had to sign in to iBooks, then iTunes. Single sign-on would be swell.