The theoretical transfer rate for USB 2.0 is 400Mb, which equals 50MBs.
USB3 is, of course, faster.
Here is a link to a Sound-on-Sound article about USB ports. But as with most everything, this is not a "one-input" problem.
The actual measured data transfer rate of USB 2.0 is all over the place. Sometimes that is due to various OS problems such as drivers, chipset, bios and other internals, sometimes it can be due to hardware implementation methods that, while conforming to the usb specsheets in theory, do not always perform that way in the real world for various reasons.
"Transfer Rate" and "Transfer Time" can also differ for some of those reasons already mentioned. Doesn't seem to make sense that such should be the case unless and until we understand the difference between "burst" rates and sustained transfer rates. Burst rates are good for most common tasks, but when the need is to transfer lots of large files, such as we encounter with Multitrack Music apps and the like, it may be problematic as vs the use of hard drive via the same USB port. Keyword there is, "may". Some motherboards seem to handle these things better than others, then there is the fact that some memory sticks themselves may also be not as good as others at this point in time.
http://www.convert-me.com/en/convert/data_transfer_rate/dUSBtwo.html Note that the above is not a Boolean argument. Take off the digital hat of "either/or" "one and zero" "all or nothing" and that leaves us with a qualified "try it and see how it works for you and your machine" as it could go either way at this point in time.
And also bear in mind that it is the intrepid experimenter that is willing to try working with the different or new idea that often blazes the trail in this sort of endeavor, maybe finding out key pieces of essential information along the way, such as possiblities of isolating certain brands and models of USB Memory that work better at it than others, same would go for the other variables, such as the computer motherboard in use, the implementation of that board's usb hardware, plus the way the drivers are written that can make differences here.
If I was to go about this experiment with BB2014, the first thing I'd want is complete and thorough backup system, such as also using the hard drive alongside the stick until such day as the stick had proven itself. I would also not want to be a Noobie to the Band in a Box program itself, as the learning curve of using Band in a Box is one thing and there could easily be problems encountered that might be part of that kind of situation, or might be caused by use of the memory stick - and it could be quite frustrating at that point.
--Mac