The difference in construction quality is huge, for the driving lamp assemblies:
Hella 500FF on the left,
PIAA 520 on the right. Hard to tell but the Hella uses just one bolt friction fit against plastic to establish beam elevation, the plastic is pretty much guaranteed to compress and become loose and require retightening PIAA uses two bolts and metal-to-washer-to-metal friction so once it's on and torqued down it's set until something hits it or bubba leans on it.
PIAA's relay on the right, though I guess there's no way of knowing what's inside it without taking it apart. But it's a whole lot heavier than the Hella relay on the left. You can also see that the Hella wiring is just bare ends you have to crimp yourself, everything clicks together on the PIAA's.
Wire gauge, Hella on the left
PIAA on the right.
Here is "what's in the box", minus one lamp for each set. The PIAA's cost 4 times as much, real world retail - but at least there's more to it than just a name.
But you can buy a whole replacement pair of hella 500s for the price of one replacement glass lens for a piaa 520 and that is worth considering too.
I went with
piaa 410s on my ram because of physical dimensions and am still waiting for the upfitter switches i ordered a month ago.. So i have no idea how well they illuminate but the construction quality and engineering effort on them appears very good so far.