I bought these stands to replace some that had worn out because I was intrigued by the clamping mechanism. I cannot be more pleased. They're very well made and extremely stable and the clamps are superb.
Instead of pinching the tube at a singular point, like the usual screw knob type system, these seem to clamp around the whole circumference of the tube which seems much more secure, plus you can't over or under tighten them. They are also even quicker and easier to set up.
If there is any negative, it would be that the clamp levers are plastic and not aluminium (as I was expecting) but despite this, they do seem very durable and if they do break, replacement parts are readily available.
There are a few options available in this price bracket but I would say these are the best of the bunch and probably even better than quite a few higher priced options.