Mine goes out of warranty in Feb and seems to be running great. I am still undecided on whether or not to buy one. I believe Pegasus also paid around $600 for a warranty, which seems pretty reasonable.
I spoken to the owners or service managers at three dealerships, asking what they thought of them and to a man they didn't think they were money well spent. They said there were few problems with the Rocket and that Triumph has been real good about taking care of those that arise after the warranty runs out. I've only had one, it was on my BMW GS. It covered engine and drive train with a $50 deductible per claim.
I want to get about 20,000 miles on mine before the warranty runs out and am pretty close.