The double wall insulation looks good, but I am always looking for a neck wide enough for standard ice cubes.
there are lots of stainless steel wide mouth versions in the market - the hydroflask is nothing new....go to any online store that carries trekking equipment and you'll see various styles of stainless steel mugs with a wide mouth...
but we only use them for hot drinks/soups when we hike...though they also work for cold...
but for water we just re-use plastic bottles that we carry in a special bottle carrier with straps that can be worn as a backpack....very easy and the backpack style carriers are very inexpensive....just a few dollars and they last forever....
we like to freeze the bottles overnight so that we have ice cold water the next day...
the carrier keeps the bottles cold...
for us, it's the most convenient method for carrying water - the same method we use when we're hiking...
it's what everyone uses where we live...many people carry them around every day, not just on hikes (since you can dehydrate in the blink of an eye where we live - as happened to a girl here last week...she's now brain dead - just from becoming dehydrated while hiking up north last week)...
another advantage of our carriers, they're rare at WDW - so when DS left his on a ride (can't remember which one), it was very easy for the CMs at the central lost and found to figure out they had it...it was the only one they had there...
i finally found a website, so you can sort of see what i'm talking about....it has backpack straps (you can't really see them in the picture - you only see one partially, but there are two straps, just like on a backpack)...it's very comfortable to wear...it weighs nothing until you put a bottle into it, but with a full 1.5 liter bottle it's still very comfortable..
i see it costs NIS 29, which is a little more than 7 dollars (though i think i've only paid 20 shekels, which is about 5 dollars)..
http://www.hagorshops.co.il/aecommerce/c1415/19439.php
there are also smaller versions for small bottles.....that's what the kids always carried to school with them when they were little...