Well I guess that's another reason for installing Linux on a flash drive rather then on a VM!
I have a few USB 3.0 ports on the new build here but still have to wait for those initial prices to fall on 3.0 flash drives now seen since they typically run for upto twice as much or more then the 2.0 version. In actuality however the speeds incated any drive is capable of is the maximum you could generally expect to see.
Most of the time those are rated by use for Windows or Apple/Mac however not necessarily including the open source lot there as far as OSs are concerned. Different OSs of course are seeing things in a different environment to begin with ubuntu being one of the smaller distros there.