You're right, it's my Harry Potter T-Shirt that means I'm not a nerd
As long as MCE is already open then it really is that fast, if it has to launch the program then obviously it takes as long as your PC takes. The only visible clue you've switched programs is when switching back to XBMC there is a slight flicker for about a millisecond that you can't see in my Youtube video which I think would be solvable if it was bothersome. It's not like you can see the desktop or anything, I can't really describe it as anything more than a flicker that is probably caused by the PC switching from True full screen (MCE) to filled screen (XBMC). I could set True full screen in XBMC and see if the issue went away, but that causes another issue for me elsewhere believe it or not, and like I said it isn't noticeable unless you're looking for it.
The switching works by launching MCE over the top (rather than focussing), so if the program isn't running it will still work. I added the additional commands to open straight to Live TV so you don't get the whole Media Center startup noises and logos and ugly menu.
I normally have it launch straight into live TV rather than the guide as Neesha tends to be the only one that uses it nowadays and it's always switched to the same channel (Gems TV).
I set the switching functionality up ages ago when I was an Eventghost kinda guy to be done by remote, so Eventghost handles much of the switching, but I could set this up via Vox instead now I'm a bit more knowledgeable. Now that I can use Vox to navigate MCE I might be more interested in watching TV occasionally as I could set up shortcuts to favourite channels and use Vox to jump straight to manly shows about cars instead of girly shows about jewellery.
The two do play nice, but obviously you have to have Vox turn groups on and off as you switch so that the "pause" and "resume" functions don't start XBMC playing stuff in the background. When I say "I want to watch live TV" it disables the group "XBMC simple actions" and enables "MCE", when I say "Switch back to XBMC" it disables "MCE" and re-enables "XBMC simple actions".
I shall do a video tutorial soon in case others want to do it, but I may see if I can achieve it in Vox instead of Eventghost and then have it trigger as an event from Eventghost in case I still want to use the remote.
-P