Just my own opinion, but I like the new sending units. The new ones are made from stainless steel (usually) so they do not have the rust pinhole issues the original ones do from condensation in the tank.

And soldering or using JB Weld to fix the leak he has, might just be a bandaid for an undetected internal rust issue along the section of pickup tube still in the tank.

I have pulled some that had either lost a good 6" or so of tube into the tank, or had so many pinholes that they wouldn't pickup fuel anymore. Probably from being parked for long periods of time and allowing the condensation to remain at a set level and do its work.