Spectra or quanta??? Help!!

Both are FUEL sending units.... the one selling spectra says MINE is BEST....the ONE selling QUANTA says MINE is best. they are both areound the same money....BUT neither can tell me which one is a non linear variable ground and what the specific OHM ranges are??? seems kinda weird that the vendors have no idea what this basic info is...but they do not. I have learned from Autometer than quite a few of the aftermarket sending units make their gauges go crazy....and I have ONE!!! 7 out of 9 people that I trust have told me offload the ebay sender and get a decent one..... here is where we hit the wall

WHICH ONE IS DECENT and which one will work with the AM gauge?

I only want to pull that tank ONE TIME...anyone have direct experience with either sending unit and AM gauges?