Judged solely on sound output level, the Hercules XPS 40 system scores only moderately. Even cranked all the way up they just don't get loud enough to fill the room. They should be plenty loud for sitting right in front of the computer though. Sound quality is pretty good however, there is very little distortion even at max volume. The Logitech system gets louder but crackles at high volume. Comparing the tone between the two, the Hercules beats out the Logitech, but not by much. Neither system reproduces low frequencies very well, you just can't get the fullness of bass from such a small driver and enclosure. The highs of the Hercules are a bit richer than the Logitech.
I plugged my TekNmotion Yapster headset into the headphone jack on the control module to test how they sound through the Hercules system compared to plugging them directly into the sound card. The first thing I noticed was that I got some crackle and either a left or right channel dropout sporadically depending on how firmly I pressed the connector into the jack. There seems to be a loose connection somewhere inside the module that is not making good contact. By wiggling the connector around and pulling or pushing it slightly in or out I managed to find a spot where I got a noise-free stereo output, but movement of the module was very sensitive. Additionally I had to adjust both the headset volume and the control module knob all the way to maximum, with the onboard sound volume set to 70% or more in Windows, in order to get a decent output level. And the headphones sounded like they had more lower bass frequency response than the Hercules speakers did.
Testing the line-in jack yielded similar results as far as the volume level was concerned. I plugged my MP3 player into the jack and had to crank the volume knob all the way up and the volume level on the player about 75% to get a decent amount of sound from the speakers. I did not have the same problem with the jack cutting in and out or the noise like I did with the headphone jack. This is a nice feature that the Logitech system doesn't have, and the ability to plug in an MP3 player or other audio device saves from having to purchase a separate dock or speaker system for that.