I recently purchased and installed a DiamondBack X SE for my 2008 F250. The X is a designation for their product with the LineX spray on option. The SE version has a 400Lb load limit on top of the cover. They make an HD version that allows up to 1600Lbs to be loaded on top of the cover.

The product was packaged nicely and delivered on a wooden pallet. Installation is truely a one man job and took me about an hour to get installed and lined up evenly front to back and side to side. I could probably do it in 30 minutes now that I have installed one. Fitting the latching mechanism took the most time, but works very nicely.

I don't see how you could use a gooseneck or fifth wheel without removing the entire cover, but removing it and re-installing it requires minimal effort/time.

Very nice cover - definitly expensive as tonneau covers go, but man is this thing nice.

I had an Advance Cover on my last SuperDuty and loved it, but there are a few things I like better about the DiamondBack. Load capacity ON the cover, gas pistons that hold the cover open for you, much more refined locking/latching mechanism, and no rubber seals that have to bend & fold like on the Advance Cover (Advance customer service is top notch - they always replaced them for me free of charge - shipping too, but it was still a hassle to replace them and deal with the water leakage while I waited to replace them).

I'll post pic's to my gallery once I get some time.