Can't do it for my main Mac, and my secondary Mac doesn't make the cut (Early '08 MB). So I bought an Early '09 classic MacBook on eBay for $199 specifically to run the Preview and Public Beta exclusively. So far after doing a clean install from a flash drive of the Public Beta, it's running great! Almost needs an SSD though, the 5400 RPM spinner is quite lacking on anything past Snow Leopard.
When I had it on my rMBP I was having lots of bugs and being unable to open apps like preferences, Safari, Calendar, and most anything else. But on the current Public Beta, it's actually rather stable. I wouldn't trust some of the pro apps too well though, I had issues with Aperture, didn't install FCPX or CS5 though.
I tired iOS 8 as well and had to roll back to iOS 7 due to the phone not opening or getting calls on occasion, pretty serious bug for a phone, LOL. Unless you're fine with a Mac that doesn't "just work", then you'll be alright on the Beta 😎
Note, my mouse cursor totally just disappeared while I was posting this. But it's back now 🙄