Actually, everything I've read about those waterers for chickens is very positive.
I don't use them myself, but people say that the chickens naturally peck them right away because of the shiny metal... and when water comes out, they've learned. It only takes a few minutes. Easy as pie and a nice, clean setup. People seem to love them!
I personally use poultry cup waterers (like the ones sold by McMurray Hatchery) and I LOVE them. It took a little while for the birds to learn (maybe two days) but now they're great with them and they're so clean and easy... no spilled water, no poop in the water, etc. awesome! I would think the rabbit waterers would bring you similar happiness! I say go for it.