USB in build 3036 is much improved over previous releases, but there's still at least one huge problem that's causing me grief. I have a USB CAN adapter from Kvaser that mostly works well, but throughput is very slow. And for at least one application I need, there is about 20 milliseconds of latency between transmission of data by the device and its receipt in the Windohs application. This latency causes the application to time out. The same app with the same hardware works on a PC, and it also works on an old 867 MHz G4 PowerBook running VirtualPC. In both of these systems, latency is on the order of 1-3 msec. I don't know if this is related to any of the other issues people are having with USB under Parallels, but it might be. I hope it can be addressed soon.