Ed: Sorry to jump in late. This thread interests me because my Sears front tine rototiller is now 45 years old and it is hard to tell how much longer it will last.
My garden space is 50'X50' and the 5hp Briggs engine front tine single speed does everything I need for a good tilling job. I always thought a rear tine would be easier to handle since my front tine tends to jump around ever once in a while.
I was never much of a fan of MTD. It seemed they were a cheap-o version of better equipment, but since they have gone on a buying rampage in the past few years, they have acquired some nice brands. I am likely to try and find a tiller made in the USA or maybe a Husky, Stihl, or Honda unless this discussion can entice me to try one of the MTDs with a Chinese engine. DR Power always sounds great on their website and advertising fliers but I don't know anyone who has purchased from them.