Thanks for the very thorough report on the Costco spinner and I'm glad you're loving it.
As you pointed out, people have different requirements.
The 20" Costco Ricardo weighs 7.7 lbs, the 21.9" Rimowa Salsa Ultralight weights 4.3 lbs.
I'm not about to spring for a Rimowa, but the key point for me is weight.
My older 20 and 22" bags all weigh 8.5 lbs empty, 23 lbs. fully packed so I'm carrying 13.5 lbs of clothes and electronics. That's the max I can lift into the overhead, onto the bus and metro, and up the steps in older stations.
With the Rimowa at 4.3 lbs I could pack another 4.2 lbs to keep under my 23 lb limit. That's a 30% increase in shoes, electronics, and chocolate!
The Rimowa are terribly expensive IMO, but doing the math just now the 4 lb difference makes it something to consider when I'm flying 150-200,000 miles a year. Either 4 lbs more stuff, or 4 lbs less weight to lift.
Weight is a important difference when you travel internationally and when you're a small-ish, old-ish woman.