mongodb management service
I was at a mongodb meetup in Dublin the other night and they did a presentation on their mongodb management service (I'm not actually sure that's what it's called). Anyway, it's awesome and worth checking out, so I figured I'd mention it: https://mms.mongodb.com/
If you are on AWS, you will mess yourself when you see how simply you can set up a sharded cluster with replica sets.
ObjectRocket is pretty keen as well.