The indexes have to fit in memory, once they don't you're going to get terrible performance. Also the indexes have to match your usage patterns, if they don't

The indexes have to fit in memory, once they don't you're going to get terrible performance. Also the indexes have to match your usage patterns, if they don't you're going to get terrible performance. The advantage of using MongoHQ is it lets you focus on the million other things you need to be doing instead of learning and doing their job - we have a bunch of stuff with them, if we hired someone and moved it all in-house we would save negative thousands a month. The disadvantage of course is you're typically sharing a shared server somewhere on AWS and you may not be anywhere near them, and your indexes have to line up properly. Long running + high volume queries can mess things up too by saturating your connections plus degrading performance.