Now that I share an office with my wife, 5.1 on my PC isn't really practical anymore. So I opted to go with a 2.1 system with a nice sub (aesthetic and overall perceived sound). I have owned two other Logitech 5.1 systems in the past. The older Logitech 5.1 system I have is the Z506 , and it has to be close to 4 or 5 years old. It still sounds pretty good (3.5/5).
Before I bought the Z533 I purchased the store brand Insignia 2.1 that is/was $35. While the satellites sounded great to a certain volume, the bass was seriously lacking. The sub box looked nice, but it was weak. To compare, my roomba was running right near me and I could barely hear the bass on the Insignia. The Z533 has plenty of bass! When sitting at my disk I have it set to 1/3 max bass. I also really like the way the sub box looks with the Z533. I'm glad that it didn't have the copper colored Logitech badge on it that the store floor model had.
The positioning with these speakers definitely matters. Make sure you have your sound set up properly as well (e.g. Spotify supports 24bit 48k Hz studio, don't have your speakers behind things, etc). Some games will only support 16bit 48k, etc.
The only big issue(s) that I've really turned my head at with the Z533 after a solid day's use (on lots of different music, movies, and games) was once during a song with pretty distorted bass notes. The satellites just couldn't handle it and sounded pretty weird, thankfully I didn't have them very loud! The speakers do his, but it doesn't really bother me that much, when something is playing they sound great. They lose a star mainly because they just aren't 5-star speakers. I would say that these are 4.5 (Great) but not 5.0 (Excellent). I know if I cranked these speakers up they were tear themselves up pretty quickly, I'm sure there would be plenty of clipping.
I was originally set on the Z323 (based on reviews and online appearance) when I first went in to exchange the Insignia set, however, while the satellites did look decent the sub was hilariously small, I swear it probably had a two or three inch cone in it. If you enjoy a good amount of bass, skip the cheaper sets with the tiny subs, you'll be glad that you did.