I have a Focusrite interface and dig it. I also use Reaper and love it.
Guitar Rig is awesome if you don't want to get into the recording hassle and just record straight away. (If i had GR i would probably use it for recording demos, because i wouldn't have to set up microphones every time i had to record).
Anyways, just make sure your computer has enough power because Guitar Rig uses a lot of CPU.
All the best!
-Torsten Borg
