These are not cheap- but I like this bottle
http://www.drsfostersmith.com/product/prod_display.cfm?c=6067+10382+14626&pcatid=14626
I bought this bottle for Cotton over a year ago when the her first ball bearing water bottle failed after a few weeks. It does not leak since there are no washers or ball bearings. The water is dispensed when the bunny moves a little lever with their tongue. Both Penny and Schroeder have used it with no problems at all and there was no training/transition time.
Penny came with a water bottle- so I did not bother to replace it and Schroeder needed one the day I adopted him so I bought a regular one from the pet store- but if I ever need to replace them I hope I have time to order one of these kind. And I wish Drs Foster and Smith had the next size up too.
But anyway since I am determined to bond Cotton and Schroeder- hopefully I will just have to buy one larger bottle for them to share and Cotton can get the smaller one I already have.