I've considered the following solid folding covers but haven't purchased yet:

Extang Encore
Extang Solid Fold
BakFlip F1
Undercover Flex


My requirement is that whatever folding cover I choose will have to work with a chest type tool box mounted in the front portion of the bed.

The BakFlip and Flex fold up and out of the way allowing the chest tool box lid to fully open. The drain hose is needed to channel away water. The only way to not have a hose is to buy a cover that fits on top of the truck bed rails (e.g. Solid Fold)

The Undercover Flex is practically a copy of the BakFlip F1 but a little cheaper. It has a support rod that prevents the panels from leaning on the cab when fully open.

I believe the BakFlip, Encore, and Flex covers will help reduce temps in the bed (as opposed to aluminum panels) on hot sunny days because they are made from a composite material.

Arguments against the Bakflip include the ease of break-ins using coat hangers.

The Peragon is a nice cover as well; however, I wouldn't be able to use a chest type tool box in the bed as the Peragon folds in the place where the tool box would be mounted in the bed.

If the Solid Fold came in FRP panels, I might consider it. I don't like the idea of drain tubes either. I couldnt go with my tool box idea with the Solid Fold. I've heard the Solid Fold has issues with leaks though. Extang won't return my email.

Good luck and let us know what you end up buying.