I am considering spending the cash and getting a MOPAR brand trunk liner and reinforce the standard weak pressed cardboard. I find that my contents slide around quite a bit. ( It couldn't be my driving, right?

) I usually carry around a bag for the gym, a bag for roadside emergencies, and a laptop bag, nothing overly bulky or outrageous. Upon first appearances, this would seem to resolve the above issues as well as provide a compartment for organization.
Are there any comments on whether or not these liners and their matching trunk organizers are actually worth the investment?
What is the downside that I may not be seeing ?