Those particular clamps are actually smart. I don't have that groove on the front one that keeps the back one from moving.

And that's exactly what I fight, is the back one sliding up a little and letting the entire clamp want to pop put of the rail grooves and move even when it's tight it still wants to move.
In theory, the grooves on the rail are supposed to keep it in place when you're tightening them, but they don't.

The clamps it comes with are more than sufficient. I’ve had the Truxedo lo Pro tonneau on my 2008 for the past 9 years and it’s never had an issue. Still works just as good.

No such thing as most popular. Everyone has different needs. You want to go to a site like AutoAnything to compare features. Your "strong enough to stand on" requirement will eliminate 85% of the market, so it shouldn't be hard to find one.

They were a bear to get in place but once tightened, they haven't moved a bit.
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The only time i have had those types of clamps come off a truck, was when my sister rolled my Dakota back in High School.

Three full rotations to land on its feet again. One door gone, roof pushed down over a full 1', all four tires blown out, front bumper pushed back into the front tires, and one of the four clamps still in place with a section of fiberglass from the cap pinned to the rail....

But my long winded point is that the clamps are usually more than capable of keeping a tonneau on under normal driving conditions.

So with the standing requirement, I would go with a Undercover Classic.

Precisely why I posted the pic of mine, they do not protrude into bed space as can be seen from the pic, they sit well under the bed side rail.
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I think that's why Rnlcomp posted unobtrusive clamps. Look close.

I know! Read through page #1 of the thread. I had agree'd with Rnlcomp by ALSO suggesting finding a different style of clamps.