YETI Drinkware. Yes, it's that good. And yes, it's that expensive. Proceed with Caution. 

Coffee stains are EASILY cleaned from stainless drinkware with zero effort. Put a dishwasher tablet in, add boiling water to the top and let sit for a few hours or overnight. Rinse out well and you're done. It will clean the interior as good as brand new. We use FINISH Powerball tablets but can't imagine it matters too much. BTW, we have found Zojirushi makes the best insulated food jars and insulated thermos for keeping food hot or cold longest. But not as heavy duty built as Yeti products. You might check those out some time.

The Magic eraser sponge will clean coffee and tea stains from these with little effort.

I bought the Ozark Trails gallon insulated jug to keep water in my car. I got tired of it basically boiling in the summer and freezing in the winter so this helps mitigate the extremes. Love my tumbler but use Camelbak for bottles. My fiance tried to convince me to get a cheaper brand small tumbler but i really like the feel and quality of my Yeti and I know I will be useing it for the next few decades so it is worth it lol.

Pro tip: denture cleaning tablets will remove those stains. May have to use multiple and multiple times but definitely works.

64oz would be good for those beer filling stations

Military / first responders as well I'm surprised there isn't a line yet

I prefer Klean Kanteen because they are lighter weight and keep my water colder longer.

You should look at the new yeti lids

Have dropped my mug so many times the lid no longer seals! Time for a new one,,,have you ytied the knockoffs like rtic? Seem to work just as good at half the price.

These are so rough and abused. Like cleaning them isn't too hard. All it takes is a dishwasher tablet with hot water.