Had an Extang tri-fold soft cover on my last truck. Worked well, kept the bed pretty dry. Very easy to use and light weight so one person could remove/install it in minutes. Downside is it would flap a bit in the wind at highway speed, the foam weather stripping would sometimes freeze to the bed rails in winter, and security was questionable. Overall, simple design, easy to use and cheap.
Have a Bakflip G2 solid fold on my current truck. It's sturdy and pretty secure. Not completely water proof either and the drains tend to freeze up. The rubber weather stripping likes to freeze to the tail gate too, making it hard to open. Install is a little more difficult with the rails that need to be clamped to the bed, and it's heavy. Overall, works well but not cheap.
'17 Ram 2500 Crewcab Laramie CTD
'13 Keystone Bullet Premier 310BHPR
Hitched by Hensley