> scales fairly well at the initial stages Not sure what that means, but scalability is the worst thing about mongo (though my experience with mongo is all fro

> scales fairly well at the initial stages Not sure what that means, but scalability is the worst thing about mongo (though my experience with mongo is all from ~2.5 ish years ago). As soon as your working set of indices gets bigger than memory, performance falls off a cliff and your entire app grinds to a halt. In my experience, mysql and postgres have a more gradual decline in performance so you have some time with only mildly degraded performance to figure out a solution (plus they have more options for tuning which can buy you more time).