I have the Petroworks clutch and I really love it. You can read my product review of it here: http://www.off-road.com/suzuki/reviews/petroclutch.htm
I haven't driven with a Centerforce Dual Friction, but many have complained about it being a drag racing clutch, more of an on/off toggle switch that lacks the progressiveness we need for rockcrawling and such. Other people love theirs though, so I guess it's a matter of preference.
I did have the Centerforce Gold clutch for many years, and it worked very well for me until I wore it out. It drove very much like a "scaled down" version of the Petroworks clutch: nice and progressive, yet strong clamping power. It survived many years of abuse as a rockcrawler and as a daily driver. I have also had a stock clutch (wore it out back when my Samurai was essentially stock), and the Sachs Heavy-Duty clutch (removed it because it didn't have enough clamping power for my combination of tires, gearing, and motor).
The Petroworks clutch is my favorite. It is "soft" and progressive when you first start letting the pedal up, but once it's engaged, it does not
want to slip. It's the best of both worlds. It costs more than other clutches (except the DF) but this is a case where you get what you pay for.
I can't estimate how long it will last, but I've put almsot 10,000 miles on it now and have had no problems with it. Nor has it needed adjustment. Its only curiosity is the "sandpapery" noise it makes when I slip the clutch. It must be coming from the bronze pads as they slip before 100% lockup. Even under the slightest slipping of the clutch you can distinctly hear the "sandpaper." It's strange, but it works! [img]/wwwthreads_images/icons/smile.gif[/img]
-- Geoff Beasley