I've used the VS100 and it's quite a nice unit.
It only samples up to 96K as opposed to 192K as
the Quad and Octacapture do...
An Android Tablet with TouchDAW will work as a control surface if you
already have a decent interface...cheaper too..
Advantages to VS100
1. Built in effects - decent, not great
2. Portable - not very large
3. Can be used stand alone with a SD card (2 Track - 48K IIRC)
It's a nice unit for the price...
Never used it with Sonar...only with Cubase...