I started with a MOnster AVS 2000 which I got for a "song" (since they are ridiculously overpriced) and it was adequate untilmy system got better. Though frequent experimentation and demos, I ended up with a BPT 3.5 Signature Plus about 4 years ago. Huge improvement over the Monster in every area - my system really "opened up" tremendously. I hadn't realized how much information and dynamics I was missing until I made the change.
I have also worked my way through lots of cabling over the years as my system has improved with interesting results. I began to realize, at least in my system, that the more resolving my system became, the more of a difference cabling made. I liken this to the prior example of video differences being more easily discernible on an 8' projection TV than a 30" TV. There certainly is no right or wrong here - its all about your particular perception. System synergy is also very important - a conditioner that sounds great in 1 system might not work for another at all.
Personally, I now have all SR Tesla cabling, and will be trying their new Powercell 10-SE next week. Notice I said trying, not necessarily buying. IMO it is critical to try something in your system before committing to purchase, for all the reasons stated - you might not even hear a difference and have just purchased a boat anchor!!
So, IMO, power conditioning definitely "matters". Each person's decision as to what works best for them can only be discovered by demoing in your own system. I think these forums are very helpful to get some jumping-off points for the audition process.
