Costco used to have a Killer non-prorated warrantee but apparently that's gone now with the switch to Interstate.
Not Interstates fault--I think they realized the previous warrantee was VERY expensive for them (I used it once).

I remember back in the 90's when Interstate was THE brand, but like a lot of things, that is no longer the case.
The cheaper batts are far better than they used to be, and the greats (Interstate and the Diehards) are no longer.

And yeah...very few actual mfgers.........East Penn, Johnson Controls, Exide and I think one other make up 99 percent of the brands out there.

....and if you think about that,,,,, It means the good AND the bad batts were all made by the same people, but now the bad are better, and the good not AS good. Hmmmmmmmm. Could it be a trickle down on manufacturing technology? The batt mfgers discovered that is cheaper in the long run to use GOOD mfg methods for all their lines, cheap-to-expensive?

True for all sorts of industries.