While i have no experience with a combo machine, I have had a fragramatics shampoo machine for 20yrs. Not sure if it has paid for itself yet. Not too much use, and every couple of years have to buy a new hose for $160. The hose and the fine tubes and foam generator inside the hose take a beating from the flexing. I have a Dual vacuum next to the shampooer, and seems to get more water, and problems. I was at one SS wash in salem,ma. that had nearly 10 combo machines, so i have seen them at many washes I have visited. If you do buy one do not get one with a red top cover, the UV fades the red the fastest, and makes them look really bad.