Considerations, as some others already pointed out, are higher populations with a drill vs. row planter and speed of acres covered with larger row planters vs. smaller drill widths. With my practices mostly wheat - soybean rotation, drilling was the way to go. N0-tilling was even better. With the varieties of beans available today, cutting populations down when drilling beans is saving seed money with no yeild reductions. FWIW, any new drill for beans, should have the SI belt meters for singlation of seed drop. This saves even more seed=$$. In time of moisture shortage - having bean plants spaced farther apart helps get a little more yeild out of them vs. rowed beans where there is more compitition for moisture. If considering a newer drill the 20 ft JD 750 or 1590 series seem to be the best made for no-till use and are wide enough to cover some large acreages in a day.