There is a clear and obvious choice which method is best suited for the production of an order, and any professional commercial printing sales representative should be able to know immediately which way to go.
Let me begin by stating that the quality of the print impression is not one of the deciding factors. Before commercial printers had invested in digital equipment they would point out that digital imaging quality was inferior to offset imaging quality, and perhaps there was a time when this was true, but not today. Over the last decade, the technical advancements in digital printing has brought it to the point where even people working in the trade can not tell the difference between a digitally printed sheet or one that was offset printed. The print buyer or average consumer looking at the printed item certainly has no clue which of the two methods was used.So what are the deciding factors? The first and most significant issue is the quantity of the run.
Offset printing requires plates and set up time which is the same whether the print run is one hundred or one million, and there is a fixed cost for that. Digital printing does not require plates or significant set up time and can produce a quality impression from the first output sheet. However, digital printing is slow and there is no economy of scale. The one hundredth sheet or the one thousandth sheet, costs the same as the first sheet. In offset printing the press can run at incredible speed. In some cases the press can print more than 4 sheets a second which is approximately 6 times faster than a digital press, and that's not taking into consideration the huge difference in the size of the sheet, but we'll talk about that in another paragraph.
Therefore, in offset printing, you amortize the fixed costs of plates and set up into your run (the number of sheets being printed), and the unit cost reduces with every additional sheet being printed. In general, the number of impressions where the two methods cost the same is one thousand. Above that number offset will be more cost-effective, and below that number digital will be less expensive. So the trick here is to determine the required quantity. Usually, if a client needs 5,000 of an item he won't be ordering 500, and vice versa.