SmiteOfHand
Member
USBs still cannot handle the amount of total read/writes that an HDD can, though technology has improved greatly in that regard. It is just a little unsafe and is not recommended by Nintendo, just like Y-cable attachments are (what I use btw).
The only officially recommended combination is a HDD with an external power source.
Cheaper USB Flash drives tend to be unbelievably crappy. They tend to not handle random reads/writes well and can often wear out quicker than they should. A good enough Flash drive would be fine in theory, but figuring out where to draw the line is difficult.
Thanks for the info. I can live with that sort of risk.