I like the flexibility of my tonneau cover. I'm able to have an *almost* watertight trunk but then am able to roll up the cover and have complete access to the bed to haul large items in under a minute. I don't have to deal with having to remove a several hundred pound shell everytime I need the full bed. It all depends on how you're going to be using the bed.
Edit: I have a Truxedo TonneauTrax cover. Basically a Truxedo Lo Pro with an integrated tie-down rail system. It's been through a few rain storms as well as the car wash and only a few drops of water made it into the bed by the tailgate.
Edit: I have a Truxedo TonneauTrax cover. Basically a Truxedo Lo Pro with an integrated tie-down rail system. It's been through a few rain storms as well as the car wash and only a few drops of water made it into the bed by the tailgate.