I don't know about the scratchy volume knob but I will point out two irritating problems with the Klipsch 2.1
1. Power switch is on the back of the sub. I have no interest in leaving my speakers on 24/7 and Powering the system on and off is a nuisance. I actually use my speakers a lot less than I might because of this. Maybe this is why my volume knob is not scratchy yet

2. There is one proprietary cable and the output cables from the sub to the speakers are cheaply made. Sometimes I have to jiggle the speaker cables for both channel to work. It is easy to remake the sub to speaker cable, but Klipsh's design choices are rubbish.
I like the sound of the Klipsch 2.1 system. When I purchased it it seemed like the best sound/value out of the other 2.1 systems I've heard. But now that I know about the M-Audio AV 40 I'll audition those if the Klipsch system ever fails.