I don't really see the benefit of removing the cat(s) unless your pushing some bigger HP and Torque numbers. If you got a turbocharger, supercharger, cam, intake and all that good stuff, you'll get some benefit of removing the cat(s) but on a relatively stock engine, I would only replace with a high flow. Keep it legal, keep the low end and keep the sound good.
I think on a relatively stock engine or bone stock engine, it makes the exhaust sound all raspy and obnoxious IMO. To each his own -Mike-