I have a Retrax. No clearance issues. But it does use a lot of bed space in the front, even in my long bed.
It locks anywhere along the rail. How hard it locks is adjustable, and it is really just a cone-point set screw that dogs down into the underside of the rail. It stays where I lock it if I do my part on the adjustment. The full closed/locked position is more positive.
I hitch up, roll it up to within a couple inches of the pin box, and lock it down. Keeps stuff in front of the hitch dry and out of the wind.
As someone mentioned, I did have to modify my Reese release handle, but I would call that an improvement anyway. The stock handle sticks up way too high
X2 on the Retrax cover, its been working great for me.