similarities:
-both dramas are centered around fraud and revenge
-both are thriller and mystery, as well as having no explicit romance
-the main character in both dramas has a tragic past and keeps people at a distance
-both dramas' leads hide their true motives behind a certain persona, or multiple
-both leads use their intelligence and charisma to achieve their goals
-both dramas have a character who is the opposite of the lead: naive, optimistic, kind and has faith in justice, intent on using law to punish the criminals, therefore clashing with them, even if their goals are of a similar nature.

differences:
-in bengoshi sodom, there is a courtroom setting, and the lead is a lawyer, while in kurosagi the lead is a swindler
-in my opinion, bengoshi sodom has a bit more action, which can be cringe for some, but I still enjoyed it
-kurosagi is a little longer