I installed a Gator SR-1 this past week on my truck. I picked it up for a good price. I went with it because of A the price and B wanted a water tight roll up cover. The installation directions sucked in my opinion. The best way to install it is leave the weather stripping off the truck, put together the whole cover, unroll it and size it up over the bed. Find where it fits perfect and mark the bed of the truck right behind the rear window. Put the weather stripping down based off that, roll the cover back up, clamp it down where you left the marking and your done.
Overall I am very happy with the cover, the true test is how well it holds up! I will post some pictures when it stops raining.