as far as tervis goes, i have to say i bought into it. i, like the opp, kept reading everyones comments on how they are a must. you just can not live without one. since i had not seen them around my area i made a great issue out of finding one when i went on vacation. i did find them at bed bath and beyond, lots of them to choose from. my eyes glassed over and i picked out my cup, then my lid, then the straws that i just had to have or how could my cup function properly? the friend who was with me could not believe how focused i was on this quest and as she had no want of the product she left me to my task. well i got my tervis, took a long time, there are a gizillion designs and colour choices. went to the cash and gave the cashier my $40 for all my parts to this wonderful cup.
when i got home i quickly took out my prized new item and filled it full of water. didn't taste at all like $40 water, in fact it tasted like water. maybe i need a hot drink to get that 'specialness'
nope, that didn't work either. very slowly i realized i bought into 'hype'. sadly, i wish i had my $40 back.
my point is tervis is not cheap. its also only a cup.
some argue the merits of the tervis cup and i get that but you need to know going in the cups run anywhere from 15 to 25 plus there are lids you can purchase and cup holders and straws, it just goes on and on. having said all this (and it was meant to be tongue in cheek) i did buy the small cup on the cruise but it was because we had money left from our obc and it was the last day of our cruise. i like to look at it but it is to small to use constantly, it sits on a shelf in my cupboard until the day i need the room for something else and i give it to goodwill.