I don't have the exhaust and have never heard it in person, but from what I see online, and what I have read, it sounds like a decent setup for the money. some have said it does NOT drone, some say it does, but I suspect if it does, it is on the low/tolerable side.
if I were to get rid of my Pedro exhaust, I think I'd get the NHP system. but $2000 for a entire exhaust is NOT cheap and the reality is, despite what the sites claim, I doubt you'd see much of any power gain from the system.
some where claim these exhausts can actually decrease power...but I'll let the "experts" address that.
I do thin it sounds cool.
FYI - the "coolest" exhaust I have heard, via the internet, is the RUF. I love how this guy's car sounds.
http://www.youtube.com/watch?v=6wMrXv1lvYs
it's 4 minutes of the owner driving around like a complete moron... but it sounds cool. similar to the NHP I think. go to 2:53.... great sounds! at least to me..