Yes, they are different. No, they don't all have warranties.
I prefer Scorpion, but I may be biased because I used to own a business spraying it before my back injury a few years back. I liked it because it never faded and it was very non-slip without being rough.
My next truck will have another Scorpion liner in it. Current truck I just can't muster the effort to tear out the old spray-in liner. Current truck is proof that all liners are not created equal. Not sure of the brand, but it is peeling off, UV destroyed, and looks horrible. The other day I saw my old truck with a Scorpion liner that I sold about 3 years ago. The liner looked as nice and shiny as the day I sprayed it in there and the owner said all he does is wash it when he washes the truck.