So, the good news is that just about any folding tonneau cover will get you what you want, in that basically all of them fold and lock in place while allowing you to lower the tailgate when they're covering your bed. The bad news is that (as you've pointed out), there's a ton of folding tonneaus to choose from. When it comes to BAK's covers, you have to kind of break it down by material, since BAK has all-aluminum covers, fiberglass-topped covers, and vinyl-topped covers. The two all-aluminum covers are the BAKFlip G2 and the MX4, the only real difference is that the MX4 has a Matte Black finish, while the G2 has a more standard stipple black with a gloss look. The two fiberglass-topped covers are the FiberMax and the F1, with the key difference between the two being that the F1 is stronger and more heavy-duty. Last, but not least is the vinyl-topped BAKFlip VP, which still has aluminum core panels, but the vinyl outer layer makes it more budget-friendly. Personally, we like the BAKFlip G2s. They're middle-of-the-road price wise when it comes to BAK's covers, solid construction, and very secure.