I've always just randomly picked whichever suited my mood when these popups come up but I'd like to know if there's a clear benefit one way or another as far as Mercantization is concerned. From what I'm guessing, if you mercantilize you get more trade income but you get Diplo power hits, but if you go the free trade route you... get less trade income but less diplo power penalties? I honestly have no idea, am I close? Which route do you usually take?