Rocky uses WizDog
INDOOR DOG POTTY for: dog house training, housebreaking puppies, dog and puppy training and does very well. I change the paper in it and he goes potty there 100% of the time when inside - and still goes outside too while on walks and playing. We live in a condo, so we don't have a yard and this works great! I think the one you saw would work well, only thing I would worry is about poo being stuck in the grass and hard to clean. The little grate we have on the WizDog is a pain to clean sometimes but not too bad - definitely better than peepads!