I would like to add my testimonial to the Yanmar tillers.
While preparing and elevating a 60' x 80' site before a 6" slab was poured, and during wet, nasty weather, I used my RS1300 tiller to mix 2500# of lime, 300 Yards of clay soil, and 100 yards of crushed concrete.
Fully expecting that I had sacrificed my tiller to meet deadlines for forming, rebar, moisture barrier and concrete trucks, and running it 10 hours the first day, and 12 hours the second...I knew that I would destroy the implement...but nothing else would work, including a Deere DZ3 dozer. The RS tiller did a fantastic job, and drivers from the dump trucks stood around and watched 10 to 15 minutes at a time, as they had never witnessed anything that mixed and fluffed heavy material such as this.
The tiller, after changing the gear oil and repainting it, is now retired to mixing mulch and compost behind my YM1401D.
I would never (ever) recommend someone do this with their tiller....Just stating that I did and I can personally attest to their strength and reliability.
Mark