I have a couple bipods that are the same general style as those shown in the first post; I like 'em, as they are lightweight, fold down to almost nothing and fit into a pack or even a large pocket. They can be taken out and just shaken to assemble themselves, but that's noisy, so I usually unfold them manually. They're great; simple is better.
I've played with a few of the fancy-shmancy ones like the Primos, but the dang things weigh almost as much as my rifle, so they might be okay to leave in a shooting blind for the season but I'm not carrying them around.
In Africa, I met a bunch of other hunters who had schlepped shooting sticks half way around the world, and who had in some cases spent hundreds of dollars for the things; exotic woods, precision brass fittings, blah, blah, blah...
I took a couple feet of rubber garden hose slit open lengthwise, some electrical tape (never leave home without it), and some rubber inner-tube strips. Cut a couple of more-or-less straight branches to length, cap them top off with some garden hose taped on, and strap them together with the rubber strips. Cheap, very versatile, and...to me, at least...captured the flavour of hunting rather than the flavour of shopping. My PH loved 'em so much he asked if I would leave them behind when I left. I looked at him like he was crazy; it's two sticks and 12 inches of cheap garden hose; of course I'm leaving them behind!
