I actually prefer the rat soup. I've never had issues with smell or cleaning up. For me it's easy, just dump the water down the sink when I'm done and throw the bowls into the dishwasher. I don't let the rats drip on the floor and the snakes don't mind it dripping in their tub.
I like the idea of the rats being wet, a little added hydration for the snakes. Even though they always have fresh water, I just like the idea that no matter what they're getting hydration.