the water is ALWAYS slimy and disgusting and oftentimes stinks if you are brave enough to get your nose close to it. Also they are a pain to clean properly, that channel is obnoxiously narrow.
I much prefer the ball-valve drinkers for cleanliness but was unhappy with how difficult it was to keep them working and the fact that many of them drip out or leak. They have to be upright and the lid seals have to be good and tight so this problem doesn't occur. Also, the lids were a pain to screw on.
I now have 2 styles of waterers (both relatively new from Lixit) that I have tried out for several weeks. So far, I am very happpy with them -- my birds are well watered and the water is staying fairly clear and clean (cleaner than the tube-style waterers).
I am enclosing pictures of these waterers in case anyone else is looking and may want to try something new.
The glass ones are pretty large because I have large cages/aviary and lots of birds using them. I believe they come in smaller sizes too. They have a rubber stopper instead of a screw-on lid (non-toxic since it is made for birds); their holder is a pain to attach -- you need a wrench and a screwdriver -- but once attached holds the bottles perfectly upright. They are a breeze to clean and fill. But, they are a bit expensive. Still I think it was worth the expense for the convenience and peace of mind they've given me so count me happy!

The smaller ones are plastic and I use them for individual bird cages -- they need a screwdriver to attach the holder and you have to be careful about what size you order to make sure it will fit your cage but I love these too!! They have a red ball valve that seems to catch the birds attention, a large opening that is easy to clean and re-fill and they stay in position once you get them there so no worries about the birds having water.
I will attach pictures and more info in my next post ( have a hungry 13 year old and must make something to eat right now).
