I had the 18oz Rambler and found it too small, and I didn’t like that you have to remove the cap entirely to use drink. Ended up with a Camelbak Chute Mag, even though it felt more fragile, because of its mechanism for holding the cap. Used the Camelbak for about a year before it took one too many dings and stopped insulating. Really disappointing durability. So I’m back to the Rambler, 26oz this time, and it’s proving to be much tougher. Still annoying not to have a retainer of some kind for the cap, but worth the toughness IMO.