I had both and me lads couldn't get the hang of the fountain from the Drinkwell one so i got the dome one from Cat-it and liked that better. Preference of choice mes finks
They both have a small hum (not smell
) but i found the drinkwell a little noiser cause of the fountain running down. The dome one can be difficult to sit right in the center so the water runs over equally over the dome but i put it down to our floor not being exactly level solved that by the handy bit of cardboard under one side.
The cat-it one is better fro multicat households as you can drink from all round it and the drinkwell one has a stronger fountain waterfall.
My lads tend not to use any now but choose to drink from the pond, their water glass in on my bedroom table and the water bowls i have outside. Typical eh!!!
Have a look on ebay for both makes they are cheaper on there and i know quite a few online pet stores that do them too if ya want that info.