The USB was better on the earlier Dynavins but they had a VERY low folder limit of 196. On the V5 dynavins there is no limit but the browsing is limited to 2 layers so you cant do artist>album>song.....you can only do album>song or artist>song. Ones step forward.....one step back....
There is no size limit that I know of.....the earlier mention of 32gb was me and another guy comparing notes on why certain USBs needed to be unplugged and plugged back in to "reinitialize". We werent saying it was a limitation. We dont know why a couple of USBs would do this and the rest not, that is what we were trying to figure out.