In Tropico 4, every industry building that has not been upgraded, in easy-does-it work mode, transforms input to output at the same rate. So a Furniture Factory with 8 workers requires 2 Lumber Mills with 4 workers each; this assumes all workers have an equal skill in the field.
Upgrades/traits that increase production, do so without increasing required input. For example, a Furniture Factory with a Machining Center (+20% production), will transform 100 lumber into 120 furniture.
The unit for trade prices is: money / 100 units. E.g. 100 coffee sells at 1300 money, with a trade price of 1300.
The unit for building upkeep is: money / month. So this is the monthly fixed cost.
When not using local resources (i.e. importing), ignoring wages, cost of power and pollution, the Cigar Factory is the most efficient way of transforming work hours into profit. Without power its profit per worker is third best, only slightly worse than that of a Jewelry Factory or Weapon Factory. With powered upgrades, it is the absolute best. The second best with powered upgrades, is the Jewelry Factory, which uses 5MW less, which does not make up for the difference in profit; so even when taking power into account, the Cigar Factory is likely the best.
When allowing local resources, a fully upgraded gold mine -> Jewelry Factory chain is about 1.4 times as profitable as a fully upgraded Cigar Factory that relies entirely on import. Any logging industry is worse than a Cigar Factory.
For details, see this spreadsheet based on an examination of the source code.