Best Mail-In 4X5 Negative Processing & Scanning Service Lab (in US) in 2019???

+1 for Praus https://www.4photolab.com. I haven't had them/him scan anything, but negatives have been great (even some kinda old and cruddy film).

I can recommend The Icon in Hollywood, been using them for 120 and 4x5 E6 processing since I moved here over a year ago and have been very happy with the results and the prices.

www.iconla.com

One can also utilize this chart: https://fstoppers.com/business/use-m...ght-you-165961
It’s 2017 but still a good place to start in finding a lab.