I actually picked these up looking for a center channel and sub for a very makeshift 5.1 computer setup. For that job, they weren't exactly amazing, but on their own I was pretty impressed.
Sound:
Considering their size and price, these aren't going to be the biggest, loudest, fullest or clearest speakers around. But plugging these in and queuing up Bodom Beach Terror and I was caught completely off guard.
Whether using them as center/sub in my makeshift setup or on their own as a 2.1 system, drums, vocals and other instruments all sounded fantastic. Impact and timbre were extremely realistic across drums, singing and piano recordings. Soundstage and imaging was also quite good, probably because the desktop speakers are single-driver/one-way. I even used these as studio monitors for recording, and when I played back the recorded track my friend in the room thought we had started recording again: they sound that real.
Each of these speakers is single-driver/one-way, so don't expect sparkling and endless highs, and don't expect the tiny subwoofer to spit 20Hz frequencies or shake the floor much. Bass drops off pretty sharply below 40Hz, still audible down to 35Hz but pretty nonexistent any lower than that.
Design:
The design here is a bit odd, with a narrow subwoofer designed to be tucked under a desk or similar and two small desktop speakers. The subwoofer has a volume knob (which I found had to be turned all the way up in all cases for a good sound), and there is a small 'pod' in line with the audio cord that contains headphone and microphone jacks, a volume control and a power switch. While the audio cord (which splits into both the stereo plug for sound and a microphone plug for the jack on the pod) is plenty long, the length of cord from the speaker to the pod is not so long, and I found that to have the additional jacks, volume control and power switch within reach was difficult in most of my setups.
Equally frustrating was the length of the power cord which ran into the subwoofer, as it made putting the subwoofer under my desk impossible without a power strip or extension cord. The desktop speakers are powered by the subwoofer and will only work plugged into it. In this case, I found the cord for the speakers (which is actually one cord with a standard stereo plug at the end that splits into two) just long enough, although I had to 'peel' the cord apart to get the speakers where I wanted.
Considering the amount of times I've dropped these and knocked them over, I'd say they're fairly durable.
Overall: I paid $25 for these retail—'nuff said. For the sound they give, these are a steal compared to more expensive stereo and 2.1 solutions that will only sound somewhere between muddy and average. While they're definitely not for blasting music at a party or shaking the room with movie explosions, they're great for casual music listening and even good as monitors.