Sure I agree playing around with stuff like this can be fun however ReactOS has been in development now for 15 years and is still in its Alpha stage while in less time look what Linux has matured into in that same timeframe. 
BTW The ReactOS-0.3.15 VirtualBox VM doesn't have to have the USB Controller removed to keep it from crashing although I was not able to actually connect any of my USB Thumb drives to it.