The way I see things, tillers come in 5 sizes.
You start off with the mantis / ryobi cultivator. The sales literature says you can break ground with it. I seriously doubt it. I bought the cultivator attachment on a whim and tried to cultivate my "well tilled" garden. What a joke.
One BIG step up are the front tine tillers. These are very popular with homeowners. They will do a decent job at breaking ground if you are persistent. They have a tendency to "bounce" when they hit hard ground so you are basically hanging on for dear life while it bounces around trying to break into the ground. It works, but can be a rough ride. I still own one as it is much easier to heft into raised beds than a bigger unit.
The next step up would be a rear tine tiller. These have wheels in the front, then the tines, then the handles. These too bounch, but you get to use your weight to hold them down. Not sure if that makes them easier on your back or harder.
I personally separate the walk behind tractors from the rear tine tillers. BCS is one of the walk behind tractors. I suppose the only difference between a rear tine tiller and a walk behind tractor is that you change the attachments. They make snow blowers, spaders, plows, mowers, ... for walk behind tractors.
Finally, there are PTO powered 3pt tillers.
I bought a 5hp MTD brand tiller about ten years ago. I used it to maintain a modest garden at the old house and to prepare both the front and rear yard for new lawn at the old house. It worked fine. It was a lot less effort than digging with a shovel even though it was a bit rough on the body.
We moved a couple of years ago and I decided to bring back the garden the former owners had established. I dug out the 5hp front tine tiller and started working on it. Two full days later I was done. The next year I tried the same technique hoping that my work the previous year would make things easier. I bounced all over the garden tearing it up some, but never got a real deep dig. The ground was just too hard and I was not going to spend 2 full days at it again. I went down to the rent-a-yard and rented a 10 hp rear tine tiller. I got it for half a day. I returned it 20 minutes late with a late fee and crawled home and to bed. It was just plain mean. I did not get a deep dig with it either. Every time the blades engaged it lept forward pulling all 225 pounds of me with it. Playing with the depth setting did not help much. I went back to the front tine tiller and just dug "holes" for the tomatoes that year with it.
Finally, when buying the kubota, I made a tiller a primary item on the "must have" list. Lemme tell you, it is a night vs day difference. I get to sit on the tractor and feather the hydro petal and the machine does the work. The only "bad" aspects of using a 3pt hitch tiller are that you can not get very close to the edges. The initial dig tosses a mound of dirt where you start and you have a ditch where you stop. There may be technique issues going on, but lemme tell you... I can feel the tiller try to push the 1500 pound tractor when it hits hard dirt. I am one happy camper that the machine is taking the beating instead of me.
So, I guess it depends a lot on what type of soil you have as well as what you have going on around the garden. It makes a big difference whether you have room to manuver outside the garden or not. If I did not have the kubota I would probably seriously consider one of the walk behind tractor units. The availibility of a brush cutter, a finish mower, a snow blower, a cart, a
chipper as well as a tiller make them interesting machines, especially if you opt for the 10-12 hp model.
