Here's my 2 cents. MIT, Transparent, etc - these are filters (and don't give me that caca about how "wire is a filter too" and bla bla bla) - dude, these are filters - big ones, small ones, high pass, low pass, all pass, etc.
Now, if you've bought your rig because the quality of the components is high, how much "fixing" do you think that they'd need? I mean, if I had something like Wilson Audio X-1 Grand Slamms being pushed by a couple of Boulder amplifiers - I'd be pretty secure that my system doesn't need some filter box on it to "fix" the sound - I'd want wire that got the hell out of the way and let these incredibly high resolution components do what they were designed to do! Hell - I PAID huge bucks to have the best, why in the hell would they need to be fixed???
Now if I had some mid-fi rig that was weak, I'd want to filter the crap out of it and hopefully get it sounding ok by filtering out the nasty parts. Makes sense, no?
So there's a relationship here - an inverse relationship: The crappier your system, the more you need filtration, and the more expensive your filterboxes get. The better your system is, the less filtration you'll need until you get to real high end sound - where you'd probably want to get the dang filters out of the way and let your system escape the bindings and bloom into its full potential.
I think people tend to like filtered cables more because they get big, sexy boxes attached to their cables and that looks like its worth more and doing more for the sound than other wires. As far as I'm concerned filters can be a destructive gimmick ((because filters are by their nature "subtractive") that look good but limit the true performance potential of any truly high resolution system they are hooked up to.
And if this doesn't make sense to you, think about it this way: If these black boxes are so good, why in the heck don't the speaker companies and electronics guru manufacturers employ them in their components? I mean, I'm sure the filter companies would absolutely love to license their "technology" to anyone willing to pop a sticker in their speaker or electronic box ... but you just don't see it.
And if THAT doesn't make sense to you, what about the fact that you can go into JoBlow's HiFi and buy the "X" model of your favorite filterbox cable and hook it up to your rig ... only the filterbox company has no idea what you're hooking it up to, and JoBlow has no idea what you're hooking it up to - so how can this generic filter work optimally for your specific system? Answer: It can't. It's generic which, by it's definition, means it's not optimized/optimal.
OK - I'm done ranting.