Now that my raised beds are biting the dust rotting I've considered renting a tiller. With just me and DW in the house it's not worth it I think. Plus the used "hard fill" and there are chunks fo cement and tarvia and God knows what in there. I once found a piece of bent rebar. I had to pay someone to dig it out!
My thoughts on renting a tiller is that no upkeep on our part, my son and DH were always and still are money-ing and fiddling with it the whole time we use it and it's small so it jerks you around so bad that for the next several days every muscle will ache. I rented this one for 24 hrs, ($68.00). We used it, my neighbor used it, my son and his friend used it. We all still were done and it sat for hours. I didn't know, was going on that little one. Next time, I'll rent it for a few hrs, unless everyone wants to go in on it again. It does such a great job. I just keep looking at the garden. lol