Lots of recent interest in tillers and tilling so ...
I have an old Mantis (very small, called the "20 pound tiller) that I bought
used for $20 a few years ago. I guess it's 20 to 30 years old. I found it
was fun to use to cultivate in close spaces and to till our six 2' by 8'
garden boxes. So when I saw a new (repaired) Toro similar machine at Lowes
on clearance for $100 last fall, I picked it up. Same usage. btw, the
Mantis is 2 cycle and the Toro is 4 cycle.

Also have (for many years) a couple very old Wards front tine tillers
(bought used, one free)(must be 3 or 4 hp I guess) and I've used them to
till previously worked small garden areas and flower beds - and tore up a
few compost piles by letting it climb right up and over. One is
continuously loaned out.

A couple years ago I bought a used 5 hp (?)Craftsman rear tine tiller -
light weight and not very powerful. Again, only useable on previously
worked ground - but easy to load and off-load on the pickup. One forward
speed.

My workhorse is a 25 yo Sears 8hp bought new (end of year clearance for
$600) that is heavy, has variable speed and can break new ground if you only
take a light bite - and hang on cause these things are powerful and can
jump. It does have the swinging handles which allows you to avoid making
footprints in newly tilled earth. I wouldn't bother to try it on "rock hard
clay". It would continuously try to walk across the surface and be a bitch
to hang on.

We have a lot of clay - gets hard and opens cracks so wide you can shove
your fingers in them in this hot weather. I use a 14" moldboard plow on a
1950's IH Farmall Cub when breaking new ground - and sometimes even first
thing in the spring on previously worked ground to turn previous growth
under. Sometimes just dragging a small disc harrow around with a 1970's 8hp
Wheelhorse is enough to get started with the previously worked area.

For someone who insists on tilling "rock hard clay" I would suggest using
something heavy - a farm tractor with down pressure on the hitch and a pto
driven tiller. I suppose a high end garden tractor might do the job but I
would rather spend $2000 on an old farm tractor than $6000 on a garden
tractor with questionable ability to do the job.

Anybody else ?