I'd avoid it. It's expensive and MySQL is going to store all those blobs off-page anyway. S3 gives you nice perks like versions and you can just store the s3_name+version as metadata in your DB instead. Also if you want to do any heavy processing of your blobs outside of the DB, S3 tends to be a lot better for parallel access (e.g. hadoop jobs)

Obviously don't know your exact use case, but that's what we do.