I think everyone on here uses a bowl as the main source, but a few have a bottle as a back up because their ferrets like to dig into the bowl and empty it out. I think because of the potential tooth damage if your ferrets don't empty the bowl or you are around enough to keep it topped up it is best to just use a bowl.
Korra the Demonic Princess
Rip Mako, my brave soldier. Bolin, my snuggle bear.
Bowls are much better. Mine haven't had bottles in their cage for years. I personally would never make my ferrets drink from one, they get so little water out of that. You can have a bowl and a bottle, so in case the bowl was tipped and you didn't know they would have some water source, but I would not have it as a main source for water.
My ferrets when on kibble drank water every 30 mins or so, on raw they drink from their bowl maybe twice a day.
I've never used bottles. One of my ferrets doesn't even know how to drink from one. I just use heavy ceramic bowls, because Yogi has to stand on the bowl to drink from it. The only thing that kinda annoys me about bowls is when they'd put their kibble in it. They always try to drink water while eating and they'd drop it. But that's not really a problem with raw I think
I have large aluminum dog bowls stuck inside large cat litter boxes (this keeps the water sort of contained and prevents dumping on the floor). The kits are terrible for swimming in the water bowl and have done ever since Momma Lola brought them upstairs. The litter box keeps the floor reasonably dry unless they do more than snorkelling. ciao