I prefer water bottles for my syrian only because I'm a paranoid hamster mommy and worry she might prefer to roll around in the water rather than drink from it. Daisy is quite the little trouble maker and I wouldn't want her to get wet tail or drink from contaminated water, so a water bottle works for me.
I bought the "regular" size, it holds about 8 oz. Honestly I only got it because it was purple and that's my favorite color, haha! But she never finishes it all in one night, I'd be worried if she did. I even put a rock underneath the water bottle so that when she takes a drink, it files her nails down a bit at the same time. I refill the water bottle every other day, it's okay if it's too big. As long as your hammy can drink from it it's fine. I've only had 2 issues with my water bottle. One that I used velcro to attach it to her bin cage and it kept falling, so I made a water bottle holder to get rid of that problem. Second, one day I had noticed that when I tapped the spout, no water would come out because the little ball was stuck. I realized that Daisy must have accidentally trapped a seed in the spout and couldn't get water! Thankfully I check every night so she must have only been without water for a couple of hours at most.
Apologies for the long response, it seems as if I'm more passionate about water bottles than I thought!
