It depends also on who you play and if you want to unlock some funky units. Having China or Holy Rome could lead you to Bulb MC/Machinery/Engineering for a CKN/Treb or Landsknecht/Treb rush. Just avoid Fishing. You can also work with GE, if they should pop up.
Academy looks extremly good on the paper, but I rarely feel a big difference. I suppose you need more modifiers like Burocracy, University, Oberservatory etc. to make the Academy worth its investment. This would implicit though that an EARLY academy is a waste of the GS.
I build early academies sometimes, when there is nothing important to bulb, too early for a Golden Age and a settled GS not attractive neither. In such a case, it is just a logical choice to build the Academy NOW rather than let the GS sit in the capitol for 30 turns. But I never see a big research boost from the Academy. Maybe it's because I usually do not play FIN leaders.
In case of a HA or Construction rush, I would usually bulb Maths. Because on IMM, AI techs too slowly and on Deity, they most of the time don't trade it.