The USB one has virtualized surround sound BTW. Does that change your opinions?
If not, I'll get the 3.5MM since it is cheaper.
Not really. That virtual surround comes from a very low quality mini soundcard that isn't even soldered. They just hot-glue those things and call it a day. I'd rather have the option for analog input to a legitimate soundcard at a later date personally, since you can get superior surround sound on a card as cheap as $49.99 and it's an investment that can last for several PC-builds.