I’ve now had interactions with the two heavyweights of plumbing fixtures in America, and can provide the following results.
Short version:
Moen seems to keep parts longer than Delta, and is thus able to offer warranty parts for a longer period of time. This is only anecdotal, but provided a sharp contrast.
Moen offers overnight shipping for $25 (not outrageous) and that one $25 payment applies to all shipments related to that order. Delta - unknown, as they didn’t have the warranty parts I needed.
Long version:
In 2014, a Delta faucet on a vanity sink in our master bath began to leak. It was not just an O-ring or washer replacement, and was about 12 years old. I called Delta for a warranty replacement and was informed that they no longer stocked that style, but they were happy to offer me a replacement faucet, up to $400 in value. Well that was just fine … except … they would only replace one fixture. Our master bath had two vanity sinks, a tub fixture and four shower fixtures.
After multiple conversations, moving up the food chain, it became apparent that this was their SOP and we were SOL. I ended up taking a replacement faucet from Delta, reselling it, and buying the correct, matching fixture from an Amazon reseller. It was a royal PITA.
Jump to 2023, and our Moen kitchen faucet handle (14 years old) flies off the faucet. My initial interaction with Moen was pleasant and the service tech said that she was shipping everything necessary to fix the problem, along with a new spray wand due to a rubber cover beginning to fail on the spay/stream button. She offered 07-10 day shipping at no charge for warranty claims. Two-day shipping was $20 and overnight was $25. I opted for overnight, and she assured me the spray wand, although back-ordered would also ship overnight when it came in stock.
Moen came through in all aspects.
This is only one example, but if we ever build another house, I will opt for Moen plumbing fixtures.