A Brita filter bottle, it takes out the funky taste and fits any kind of cup/bottle holder you may have in a stroller, backpack or hip pack.
You can also get insulated sleeves to put them in.
The Bobble filter bottles are shaped a little funny.
For kids anything they can hold and open up themselves. Process the water through the Brita bottle first.
This.
DH got a Brita filter bottle on sale at Target before our Aug 11 trip. We still love it to bits. My Bobble bottle got chucked in the garbage. It was not comfortable to carry.
Plus, the Brita bottle has removable/replaceable filter. The Bobble needs to change the whole cap.
I have purchased a few of these and love them. They are a little pricey but the water stays Ice Cold all day and the bottle doesn't sweat even in the Orlando heat and humidity. There use to be a Disboard discount I will search a little and see if its still out there.
http://www.hydroflask.com/
ETA: The discount code is DIS 10% off then go back when you receive your bottle and register it with the code on the bottle and they will donate money to a charity (list on site) Give Kids the World I believe is one of them.