We loved our waterdog, and so did our dogs - it didn't take long at all for them to figure out how to trigger the unit to dispense water, and it was nice cold water straight from the faucet. Our only mistake was leaving it on the faucet in the winter. It got too cold, cracked one of the pieces and started leaking. However their customer service was great, and they sent us a replacement part at no charge.
You can buy the Water Dog online from Amazon.