I can't help but wonder if any of these places test before/after? If they are testing, how are they doing it, just a voltage reading? I've seen quite a few read 48V at all settings but still be junk. Do they stake the components after they peel off all of the old staking compound? Hmmm.... these are things you should be asking.
They warranty for life, sure, but what are they going to do when you're stuck on the side of the road with a 30' gooseneck and your whole family in the truck. Send it back to them so they can resolder it? Do you sit on the side of the road the whole time waiting? Hrmmmm....
I know when I fix FICM's for customers, I actually put it on my own truck and drive it around for a few days, and also do some cold start testing with it. I also stake the components back down like factory. From what I've seen, Swamps doesn't even stake the components. I have only seen a couple opened up though, perhaps they do now.