I had an Extang Encore, similar to the Fold-a-cover below. Really liked it and the ability to get access to front of box. Only problem with it is, when panels are folder forward so rear of box is available, it adds about 3" to the top of the box, thus if you have 6" clearance to the bottom of trailer and making a sharp turn, you need to be very careful as you now only have 3" clearance. That is were I think the Bakflip is better as the panels are vertical along the back window. Yes, blocks your view out the rear window, but no clearance issue.