It barely matters. Compose.io's mongo db service is also in aws east. It's simply a matter of pasting the mongo connection url they provide. The scalability they provide would be a waste of MDG's resources to build themselves. Perhaps they could automatically integrate with compose.io, but other than that its identical to what MDG could ever provide.

So unless ur bummed about costs again (i.e. the Compose.io costs on top of Galaxy's costs), U pretty much have everything u need now. It seems soon they will provide a cheaper account.