I think the idea of a USB 'scope (and logic analyzer, and pattern generator) is fundamentally brilliant. Why try to implement the display and the controls in a hardware box when you already have a best-in-class user interface sitting on your desk? ("Best in class" assumes the GUI designer understands the problem domain, but I digress.)
Of course, the poison apple in this Garden of Eden is that the vendors need to keep up with the changes in operating systems, and provided driver and other software updates in a timely manner. Unfortunately, this seems to be given the short shrift. The last thing you want is for a $2,000 box to be turned into a brick because the vendor doesn't want to update the driver for the next version of the OS.
-a