I bought a set of these for my friend and tested them out. They sounded very good. I did set it up to emulate 4.1 but did not try it out. I listened to MP3s and CDs and it sounds great. Regardless if you buy this for the virtual speaker or not, it's a good sounding set of speakers.
On the side note, it does come with 2 inputs, one for front, one for "virtual" rear. So the jacks are the same as a 4.1. I don't know of any other 2.1 speakers that have 2 input jacks.