I upgraded my laptop that I don't use for audio to Windows 8 by downloading the upgrade from MS and installing right over my old OS. It was a very easy transition
  Is this safe to do with my DAW computer or do I need to do a clean install?

I went over-the-top to win8 from win7 64bit with no issues.

I moved my waves licenses to the cloud before doing so.

Your mileage may vary so goodluck!

Thanks backwoods,
     I think I'll give it a try. It will be a good chance to test out my Acronis purchase if something goes wrong

check your focusrite drivers for Win 8... my saffire pro 24 does not have Win 8 drivers on their site yet and they don't guarantee it.

The saffire mix control 3.01 drivers are on the Focusrite site. Dated 12/19/2012.
I'm installing Widows 8 right now. I'll keep you posted

I upgraded my "utility" computer to Windows 8 over the top of a Windows 7 installation. Something went wrong. First it started OK but after while there were a lot of problems, some crashes and then a totall refusal to start, I think caused by an incompatible application. In the end I used the recovery option to take it right back to virtually a clean install. Since then its been fine.

So proceed with caution.

I don't have the option to do any thing but a clean install on my DAW as I am on Vista, but even if I was on WIN 7 I think I would go for a clean installation.

 The install is done. I updated the Focusrite stuff. I just fired up X2 and played a project perfectly. 
   I'm tired and I'm going to sleep. I'll test it out some more in the AM. 

  Thank you all for your input.

Delete the windows.old folder on the C drive after you upgrade. Sometimes it takes up a lot of space. Just make sure you don't need anything in there from your old install.

 The only glitch so far is that my UAD2 stopped working. Device manager exposed that my USB 3 PCIe card driver was hosed. I uninstalled that and restarted my PC and both the USB and uad came back and work fine.
         Just ordered a touch screen 

FWIW, You *can* do an upgrade install of Win8, but (obviously) it's best to start with a fresh/clean install.
Otherwise, you're inviting potential issues...
Some folks will tell you this isn't possible with an upgrade disc.  It *is* possible, you just have to make a registry tweak prior to authorizing Win8.