I just bought a used 6x10 DD for my MXT. Have used it a couple of times, so far I like it. Biggest thing I notice is it runs more stable and seems to be quieter. I am thinking because of the knife edge search pattern versus the round/conical of the 9.5. Seperates alot better, of course thats what the DD's are designed for. I have not made up my mind on depth though. I think the 9.5 is a bit deeper in non mineralized soil. I have not tried it in large areas with ground reading mineralization 70+. I did go to a sledding hill that I tried before when I first bought the detector this time last year. I spent alot of time there and thought I would have cleaned it up, ended finding 3-4 dimes and a bunch of pennies that were 4-5 inches. I would still like to try the 10DD. I do mostly woods and feilds so I think the 10DD would be a bit harder to use given the open coil design.