It does get a little slicker once sprayed with tire dressing but not that bad or dangerous.
I have used a few different tire dressings (AA, turtle wax, etc.) and they all worked great some just have lasted longer than others just like they do on tires.
Line-X is a little different than Rhino liner as it is harder, and seems to grip onto loads better form what i have seen. Try a few different tire dressings and see which ones you like.
I would choose one that is a little cheaper as you will use quite a bit on the spray in liner.