It would be a great idea if you need both units, because it would save you floor space and at $200.oo plus S/H it's pricey. My only fear would be... What if the pet device continued to fill the watering bowl and empties the entire 5 gallon container. What a mess! If it happens with the smaller bowls there is only a small amount of water to clean up off the floor. This has happened to me once in the past 5 years. The water - leveling device, got stuff in the upright position, while I was fill it. What a mess!

I never walk away while filling now!

Just in case.
I too love the watering dishes. I have a watering dish that filters the water for my cats and I can put it in the dishwasher as needed. I bought it from PetCo and I have the matching food bowl also - both in White. Now Lola (my Yorkie) drinks from it also. I paid $35.00 for it in the store but it's worth to me, because I have had it for 5 years now with no problems. All I have to do is purchase the (2-pack) filter pad for it about 4 times a year. I Love Them!
Pet Drinking Fountain: Pet Water Drinking Fountain, Petmate Fresh Flow Purifying Pet Fountain at PETCO