Tracktion was one of the first DAWs I played with. I remember liking it a lot, and planned on purchasing it until version 2 put it out of my price range. It's good to see the original team pick it up again.
It seems to run OK on Vista. It took a while to load up the VSTis - it made multiple attempts to reload modules, and each attempt popped up a dialog box, each requiring an "OK" button to be clicked.

It's was a bit hard to figure out the navigation - there's a lot of context-sensitive stuff that requires the right things to be clicked before they appear.
After cracking open the manual, things started making sense. I don't think it'll draw me away from my current DAW, but it still seems a nice application.