I have the simple Pet-co brand water bottles, but I've found they start to leak quite fast, and have to be replaced often. (However, this is common with most water bottles!)
When I was first teaching my glider's to use a bottle I put 2 oz. 100% apple juice in their 8oz. bottle, and this really incouraged them to drinmk from it!
Also, as Kazko said, some bottles are to hard to drink from, and the glider's just choose not to drink. AVOID THOSE BOTTLES!