I'm not sure if there are any others like it, but Rhino Liner seems to be in a class by itself. To my knowledge and experience, it's about the only one that stays somewhat pliable for any stretch of time - most all of the others I've seen basically turn into 80-grit sandpaper after a short period of time (as-in, after it cures). I've personally used Duraliner, and seen many examples of Line-X, Herculiner, and U-POL Raptor... I've also seen an entire Jeep painted with Durabak, as well as one completely sprayed with Rhino Liner.
Rhino Liner has my vote, hands down.