I agree; they work great. I bought a set from them a few months back to move materials for the barn I'm building and to provide a platform to stand on, rather than standing in my tractor bucket. Mine are rated at 2500 lbs. They flex somewhat under heavy loads, but they seem to handle the weight no problem. The most I've lifted with them so far is probably around 1800 lbs.
The only real issue I have with them (and this is probably universally true for clamp-on forks), is that they move side-to-side pretty easily. It's not a problem when lifting pallets or other objects, but it can make things a little dicey if you're trying to stand on them high in the air. Also, don't even think about trying to "nudge" something sideways with the forks.
I also wish the screw-down clamps had "feet" which turn freely like typical C-clamps do, so that they didn't mar my bucket when I tighten them down.
Again, those are more observations than complaints. Otherwise, it was $190 well spent.