Curious what bugs you're seeing? I've used the qt client quite a bit on GNU/Linux and I haven't had any troubles. Again, just curious.
I'm on OSX. Using the latest 5K iMac loaded with the latest version of OS X.
I see two issues right off the back:
1) Clicking the Bitcoin-Qt icon from the dock doesn't load up the windows. Instead I need to right click and click Show / Hide to get it to pop up.
2) Other than the overview icon, the other 3 (send, receive, txns) are pixelated and not optimized for the retina (hiDPI) display. Nor are the icons in the recent transactions list. And the checkmark in the transaction list row. Pretty much everything isn't optimized for hiDPI displays other than the overview home icon. Kind of disappointing because it's such a simple fix and it would prepare it for future displays. I'd like to help provide cool looking icons that are hiDPI ready.
2) Hi-res icons would be nice.