We didn't hire any experts, instead we educated ourselves on the matter. For example, one of the first steps we took was to run some rough benchmarks on Pg to s

We didn't hire any experts, instead we educated ourselves on the matter. For example, one of the first steps we took was to run some rough benchmarks on Pg to see how it behaved compared to MySQL (https://github.com/olery/rds-shootout https://github.com/olery/rds-shootout). Followed by this was mainly discussing PostgreSQL vs MySQL with those who used either one (or both) in production for a somewhat serious workload. Backup/restoring is handled by Amazon RDS in our case, in the past we had a custom backup system for Mongo that backed data up to Amazon S3.