My original heater core seems to be leaking and I'm thinking about replacement vs upgrade.

Has anyone tried a new aftermarket heater or heater/AC unit?
How does performance compare to the original 'deluxe' unit?

Here's what I'm looking at:
https://www.classicparts.com/1955-59-Heater-Defroster-Assembly/productinfo/68%2D991B/#


'59 Chevy Suburban, NAPCO