Both the BCRH and the DCRH will remove the cat, so you'll have to figure out a solution to pass emissions.
Bang for the buck? Well if you go by this post..
200+whp Club
You can draw a couple of conclusions:
1. The DCRH is really THAT good.
2. The BCRH folks just didn't have enough money afterward to dyno their car (lol, sorry, I had to).
Longevity may or may not be an issue with the DCRH. Problems have been reported but most DCRH owners swear by their header.
I personally have a Vibrant RH but that's neither here nor there. lol