I own the z-680, z-5500, and now the z-906 I could not be happier with these speakers. They sound fantastic. Some people say they are expensive but I dare you to walk into Best Buy and find a better 5.1 system for $399.99. Trust me you wont cause I used to work there.
Excellent sound overall; The bass will not disappoint; Sound is super clear and loud without distortion
Logitech replaced the control module from one with a LCD display to just lights; Still gets the job done just in my opinion not as nice