PAUL BURNEY  I am a former CodeTek virtual desktops user who recently switched to this application when I got a MacBook Pro. My Virtual Desktop needs are pretty simple - just have a set of applications that are always displayed on a particular desktop.This app works great and is very stable for that purpose. I haven't tried all the extra features.

The demo worked for me without any problems. The app has a nice menu to switch between your desktops and you can customize the icon to your liking which is nice. I typically just use keyboard shortcuts for this, though.

The arrangement of desktops is a simple list that cycles which is how I'm most productive. I've tried 2D sets / grids of desktops in other programs and always found it to take too much thought.

The current beta has a bit more polish than the previous release and I've found it to be stable on my MacBook Pro and on my G5 Tower.

YouControl Desktops also doesn't exhibit the annoying "unfocused dialog box" issue with Adobe Creative Suite CS 3 of which other similar applications suffer.

The only feature I miss from CodeTek is the ability to have an external monitor not do switching. A workaround is to set those applications on the second monitor (e.g., EyeTV) to "display on any desktop" then turn off the desktop transitions.

All said, the software is well worth the money for me.  
(Version 1.3b1)