Some years back I was using testing. It was the year they changed over from Gnome 2 to Gnome 3. I couldn't use the stable release because my mainboard and cpu wasn't supported.

Boy, was this a hard process. It took some months until my system worked without GDM crashes. After that I changed over to Arch and been a happy Arch-er since than. I wouldn't recommend running testing.

I've heard that unstable is more like Arch linux and the rolling release model of Arch Linux works very well for me.