Spray in liners
Agreed spray in is better in many ways. noise reduction is the the biggest one I have noticed after getting a Rhino liner in my 09' GMC Sierra All Terrian. I talked to a rep at Line-X and he admitted to both products being pretty much identical, the only difference would be when it comes to the actual spraying of the product, 2 methods hot spray and cold spray. You want the hot spray technique the ingredients in the liner are better fused/ mixed and allows for better adhesion to the bed. Proper prep has alot to do with adhesion as well I imagine, I believe they do a ruff sanding with a orbital sander. I recommend asking if the the installer if they use the hot spray method if you go this rout.