Our clients usually have a lot already running on InnoDB so we always have similar setups (preferably identical except the same volume of data) to what they hav

Our clients usually have a lot already running on InnoDB so we always have similar setups (preferably identical except the same volume of data) to what they have on the side. Can't tell you how many problems we've caught that way and how much it simplifies things during deployment. If starting anew, it's Postgres. Our internal stuff is almost all running straight Postgres but a small part of our application stack is abstracted on top of it to provide document DB functionality.