Popcorn is definitely the person to answer this question with authority. But here's what I've seen and personally experienced.
Much depends on whether the ground actually needs to be turned. Much can be done with spray/seed/mow techniques, especially for fields not planted in a summer crop. Spraying and mowing summer weeds/grass onto broadcast seed has many, many advantages, especially for holding soil moisture during dry periods and preventing soil erosion. But this technique has it's down-sides as well. For very compacted soils, poor quality thin soils, and/or cherty soils, it can take years of spray/mow planting to build up any topsoil. In addition, lime and fertilizer do not become deeply incorporated into the soil without turning the ground. A seed drill is better option than just spray/mow, as it allows any type of seed to be planted, and germination rates will be much higher (and seeding rates lower, saving money). But in thin, hard soils, a drill isn't an option. It will just roll across the surface without cutting in.
Bog disks and chisel plows are about the only option for extreme hardpacked or chert soils. But even then, it's best to try and break ground right after a rain, when the soil is softest. However, just disking often leaves the broken ground in big chunks. This still helps a little with getting soil moisture deeper into the ground, but doesn't help as much for producing a smooth seed bed. Using a tiller AFTER disking produces a very nice seed bed, but if the ground is very rocky, it can be extremely hard on a tiller (and the tiller needs to be gear driven instead of chain driven).
Again, everything comes down to current soil condition and what you want to plant. IF adequate soil already exists, I would look towards drilling as a first option, with spray/mow the 2nd option (as long as only small-seeded plants are used). If the soil is extremely hard or cherty, look at bog-disking first followed by tilling.
websoilsurvey.sc.egov.usda.gov
