I EDC two 0.75L Camelbak Better Bottles. I rinse and refill them with filtered water every day. Once a week I disassemble and run through the dishwasher then allow to air dry.
I like that I don't have to pull, twist or unscrew anything to take a sip, particularly when driving. I leave the drinking nipple flipped-up on whichever one I'm using until its empty. And the inner child in me is comforted by suckling at the silicone nipple.
I used to EDC a 1L Nalgene, but the pockets on my EDC bag won't hold that large a bottle. My only complaint is I haven't found a nesting cup designed to fit the smaller diameter of the .75L Camelbak bottles.
I'm thinking of switching my EDC bag from my Northface Surge daypack to a Maxpedition Jumbo Versipack. If so, I'll go back to a 1L Nalgene but will probably put the cap from the Camelbak Better Bottle on just for the nipple.