Our German Shepherd has degenerative myelopathy and has gradually been losing the use of his hindquarters. We have been function with a rear lift, but realize that he really wants to go for walks stil...
I've used a cart for several cockers. We have one made by Dewey's. Works well, the dogs loved the freedom it gave them. I'm not familiar with DM so can't add any input there. Just throwing in my 2 cents that the dogs seem to adapt well to the carts and I've never regretted investing in it.