Other than the fact the bushed pin costs $20 more for a set of 8, what is the difference?

 

With a bushed rod the pin can turn in the rod as well as the piston so there is less chance of a pin getting tight. Yes it's more expensive to make the rod and the piston has to be grooved at the outer ends of the pin bore to accept the retaining rings.

It's easier to install a "floating" pin, but the spirol locks are sometimes tricky to remove. On the other hand, installing a "pressed" pin should be done with the correct equipment, and removing it is tricky.

It is also important that the bushed pin bores have the correct clearance with the pins. Often this is .0008 inches which is pretty small. Since pistons usually come with pins, the piston manufacturer assures the piston-to-pin clearance is correct. You often get rods from a different source, so the chances of a bad fit are higher. I've seen one "tight" pin bore in a set. The hole was very slightly out of round, about .0001 or a little less! It took just a kiss on a hone to round up the bushing, but it was important to do that.

Everything has it's + and -.