[sorenbs]

The single biggest obstacle when using aws is EBS. It offers sub par and unpredictable io, making it near impossible to operate a traditional SQL DB at any significant load. This is the problem that pushed us to explore mongodb two years ago, and i believe this is a major driver for noSQL adoption in startups.

[pkh80]

What about using Amazon's built-in database services (RDS, DynamoDB) instead?

[lucian1900]

Biggest problem with that is the lock-in. Tying technology to provider is not an option for many of us.