I know this a cycling forum, and a tiller is not a bicycle, but what the hay, I'll play!
I personally don't like mini tillers, there is no weight to them so you have to man handle them by pushing down hard to till even shallow depths, just not fun at all.
The other thing is that most mini tillers are either electric or battery powered; look, I use a lot of battery powered tools and love them, but a tiller is very difficult work, something that a battery or house current isn't up to the task at this time, you need a gas job. The only mini that I know of that can sort of due the task is the Schiller Grounds Care Mantis 4-Cycle Tiller Cultivator 7940 but the price is $375 on Amazon. But for that price you can get a bit larger one called the Earthquake 20015 front tine tiller, this one is a bit heavier so you don't have to press down as hard, it's lightweight but not mini light weight, and it's cheaper at $300.
Both of those are light duty tillers, and they are front tine tillers and those don't penetrate the dirt as well as back tine tillers, but if you want a mini then you have to deal with that inadequacy, but they work fine for small gardens, especially the two I listed and the last one more so then the first one.