Worries about long stretches of road with no water led me to search for extra large water bottles that would fit in my cages. I discovered the Zefal Magnums, which are quite a bit larger than large, "standard size" bottles. I ordered three from Nashbar.
I used them Saturday. They were not good. The problem was the spouts (or whater you call the little plastic piece you pull out and drink from.) The first problem was that when I pulled them out, they didn't stay. They wanted to go to a half-in, half-out position where the flow of water was cut in half. But the biggest problem was that they leaked a significant amount of water around the "pull-out" part, which dribbled down my chin. I don't mean just a drop or two - it was like half the amount of water that was going into my mouth!
When it happened with the first bottle I hoped I had a lemon. But no - I tried all three and they all acted the same way.
I tried lids from my other water bottles but none of them fit.
I have to give the Zefal Magnum a thumbs down.