I have had these speakers before I bought my 5.1 speakers (also Logitech). I bought those for 60 euro's about 4 years ago. They were the first real PC speakers I bought since I first always played on the sound of my monitor. Compared to that, this sound quality was great. I could hear a lot more things and a lot more clearly than before.
There also comes quite a lot of sound from the speakers, and also from the sub woofer. The sub woofer is really small and yet delivers a lot of bass. Especially compared to my new set, where the sub woofer is just huge, the quality is good. I think these speakers have a lot better quality than the my new speakers when looking at price - performance ratio.

There is also a very handy on/off button at the front of one speaker and so is there a volume control. This is a lot easier then adjusting the volume at of your PC the whole time.