I ended up returning the Drinkwell platinum and got the Pioneer Pet stainless steel big max. fewer parts and easier to clean. so far both cats and the dog like it.
It's not a Drinkwell, but my two adore their fountain. We have the Pioneer Pet Big Max. It is stainless steel and extremely easy to clean. I purposely looked for steel because I've read that it's pretty common for cats to have allergies or other issues with plastic dishes. It is virtually silent as well, which is a huge perk!