Here in New England you can run into a wide variety of soil types. On my 5 acres I have everything from heavy clay and hardpan to loam and sand- but then, we're on a ridge where I have about a 40' change in elevation from one portion to the next.
I went through the same thinking as you, and ended up with a KKII tiller. I used to use a small tiller behind a JD 112 garden tractor, and before that, my dad had a rear mount on an old Wards Chor-Trac 2 wheel walk behind tractor. If you plow and harrow, you're gonna be making multiple passes anyway, so what's the big deal about having to make multiple passes with a tiller? Make your first passes shallow- that'll tell you what you got, and if there's big rocks, the tiller'll bounce off them easier. Just be ready to raise her out of the ground if it starts to buck and bang.