I hope they pick them up. I hate the waterer I have. I've dumped the entire 3 gallons on myself more then once.Horizontal is much better than vertical, unless you have the trays under them. My last batch of meat birds would pick a nipple and three or four of them would peck it constantly until a puddle formed in the bedding, then they would drink from the puddle. Every now and again they'd take a drink while pecking, but nope not gonna drink from them.
I've heard the horizontal don't freeze as easily either.