I don't rely on the word of a retail employee on anything. It's right on the receipt. The whole "must return all items for a full refund" is being misinterpreted by some of those employees, but it's not their job to do so. You are not asking for a full refund.
Every person that's failed on...
As a pro user of it, I can say that it is more than capable. I get something like 140 cuts of 3/8" threaded rod on a 4.0. I also own the Fuel Deep Cut, but it only comes out for diameters above the m12's capacity.
Only time I even run into Ridgid cordless on a job site - or Ryobi, for that matter - is the occasional handyman type. As a contractor, performance is what I care about, not length of the warranty.