I still have and regularly use 3 Nissan (Thermos) stainless steel vacuum tumblers. I got them probably 15 years before Yeti came out with their very similar tumblers. So to call the RTIC, Ozark Trail, etc models knock-offs of Yeti is laughable. They're all knock-offs, including Yeti.
Yeti makes and (especially) markets very good products. However, there are also any number of similar products available for a fraction of the cost. Everyone's trade-off between value and name brand identification is different. To each his own.