After a weekend with the Sentry CT, I have to say that I like it. It's pretty easy to use, but, it does have to be open to close the tailgate. It rained a bit this weekend and seems like everything stayed dry in there. I am someone who looks at it as a failure if I see one drop of water, so, I'll just say that it was dry enough for me. Had things in it while drive through the rain, got back to the RV and pulled them out, they were dry. I didn't inspect every inch of the bed to make sure NO water got in, but, I didn't see any either.
I doubt that a hard roll up would be best in the ice/snow, so, maybe not ideal for those of you that have cold weather, but, so far so good for me. One thing that all of these covers likely have in common... it gets HOT in our Florida weather. Like hot to the touch to operate it. I remember when I had the original bakflip, it was the same really. Not a complaint, just part of the black cover.