I can say from experience it sounds like crap.
I switched from my stock muffler to a pypes proV muffler when I first got the car (was easy and cheap to do myself)
While I had the stock muffler off, I had the same thoughts as you... so, I ran around the block a few times... it sounds good at idle in the garage, but as soon as you hit 2500+ RPM, it starts crackling really high pitched... sounds like my old civic did when the exhaust rusted through.
Since then I've had true duals custom bent (no crossover) and glasspacks installed mid car with HUGE (20"+) tips out the back where the stock mufflers would be located. I also switched my stock bumer cover for a GT bumper cover to accomodate the second exhaust. (that I painted myself, not too shabby for the first time I ever painted a car part)
The glasspacks sounded a little raspy at first, but the more they break in, the better they sound. I've had them for a couple weeks now, and the raspyness is all but gone. I have a nice mellow tone, and a deep growl when I open her up. I do still have a bit of a high note around 4000-4300RPM, but that's fading quickly. (when I first had it done, the high note was between 2800-5000)
Only paid $240 for exhaust job. Quite a bit cheaper than any of the exhaust kits I've seen, and I have true duals, which none of the kits offer. (the 'JBA true duals' include an H connection, I wanted duals that don't interconnect)