The quick attach would definitely put the load closer in towards the pin, so you would probably get the most lift capability. They are definitely light duty. The fork mounts look like they could easily bend the back plate. Not sure how thick it is, hence why I would be concerned.
My neighbor has a set of the bolt on type. He has carried 25 - 8' x5" fence posts no problem. He really doesn't lift anything heavier than that. He does have the stabilizer bar and they "seem" to be much more stable with the bar in place.
Again, depending on what you will be doing with them will determine which you should go with.... if I were purchasing an inexpensive set, to be used for light moving, I would go with that SSQA quick attach one. Almost can't go wrong for $325......
The only bad thing that I notice with the SSQA one is that the width / spacing of the forks is not adjustable. That would be a real deal breaker if you would be moving different sized pallets.
With a 45 HP tractor, you could easily bend both those sets if you are not careful and press down too hard on the tips....