We have many. So we tested the $30. yeti tumbler against the $9. tumblers. Same ice in each, filled with water, and left alone. The ice lasted the same amount of time. Yeti ain’t better.
We just purchased over 100 tumblers, of an off brand/knock off. They work just as well as the much pricier Yeti version. Made in the same China factory, probably :-)
I remember, a few years back, a story was going around about someone who had purchased an Rctic tumbler (in a store) that actually had a Yeti bottom. Oops!
Who knows?