I think the hay bars are wonderful, they are super easy to fill. I got my daughter one for her stable for her birthday recently. She is only 4 years old but she can fill the hay bar up herself. Got to train them young :-). I got a bright pink one, she loves it (you can see it half way down...
Thanks for the info on this thread, helped me choose our new ones. We have just replaced all our automatic water troughs, had a few problems with the old galvanized ones and so far really pleased with the new plastic ones. I would definitely recommend them.
They still need to be cleaned...