I am currently using a large red and white one (pet shop own brand I think)
I use the Ferplast Sippy ones have done for a few years, very happy with them. But they aren't cheap.
I read some reviews about the sippy saying it just leaks all the time?
I really liked the look of the sippy
Biba ones are great they were recommended to me by people on here, they also have long spouts
http://k9capers.com/shop/proddetail.asp?prod=9709
I have found that cheap Tesco ones work fine, with one catch: If one wears out, I have found it best to throw away all my bottles and buy new. This is because an old bottle with a new cap will leak (and the other way round). Since I can't tell which bottles came with which caps, I make sure all my bottles are from the same batch.
With any brand, you must fill any bottle all the way up. Otherwise the air inside it expands when it gets warmer, forcing out the water.
How often does the water need changing? My ferrets (I have four and they have the same drinkers as piggys) have 2 drinkers in and will nearly empty them both n a couple of days so I swap one one day and replace it and the other one the next day and replace it. Since the piggies don't drink that much how ofte does it need emptying?/?/?/
I have found everyone of those I have bought has leaked badly. I tried to GP and the hamster size and they all leaked.