[CorsiHockeyLeague]

I have both in various iterations and here is my view.

1. Yeti is really good at basically everything, but overpriced, and the quality difference between it and Stanley does not warrant the price difference that is usually there.
2. Stanley is the best option for thermos-style containers.
3. Other than for a thermos, here's not really any reason to buy EITHER of those brands. I have a yeti colster (i.e. tall boy insulating koozie thing) and it works fine. You know what works equally well? The Camelbak version that you can always get for much less money. I have a Yeti tumbler, and it works great and has a good lid. You know what it's not materially better than? The Drinktanks ones I got for way less money in a variety of colours so everyone knows which cup is theirs at a BBQ - the Yeti's lid is better but it's not any better made or insulated.
4. If you want a water bottle, again, ignore both brands. The best I've found (great variety of highly funcitonal lids) is Klean Kanteen, and you can often get them on sale. There are other options. Why you'd pay $30+ for any of this stuff makes no sense.
5. If you're looking for an insulated cup, for example for a growler or keg pour, Drinktanks makes a top tier one and again often on sale.