Interesting, I've had no WiFi issues, no BlueTooth issues. There a few other bugs that I have, however.
1.) There's delay when you get an audible notification of a new e-mail vs the on-screen visual one. The sound is like 5 seconds late, sometimes more, sometimes less.
2.) There's also the bug of when opening a new Finder window, the selection rectangle when the mouse button is held down lags, until you go into another folder within that Finder window, then it's smooth 60FPS.
3.) Another bug would be Window resizing. It's not BAD, but noticeably a bit of lag vs. none with Mavericks, though apps like Calendar resize just fine, no lag.
4.) BIG one is the fuzzy/blurry text and fonts that appear gradually over time of using Yosemite. Details about that can be found on Apple's own forums. I submitted a bug report to Apple about this.
https://discussions.apple.com/message/26853159#26853159
5.) Finally, SAFARI! Constant hanging of the iMac 2009 27 that I'm one, where it needs to be restarted manually with holding down the power button to turn it off. Using Chrome instead and no crashes, yet. Happened with Mavericks, as well.