[_verandaguy]

Performance is definitely an important aspect, but coming from a background working at smaller companies, bootstrapping time and development time are a factor as well -- and while Postgres is easy to set up if you're familiar with it (and I dare say it makes DB design fairly straightforward), Mongo and other NoSQLs are pretty objectively easier to just get working if you aren't fluent in relational databases.

[GiorgioG]

No offense, but if you don't know how to design/develop a database schema, making it easier to shoot yourself in the foot by using NoSQL database is not the answer.

[_verandaguy]

None taken. And I agree -- but database design is inherently different under SQL and non-/noSQL. Constraints and relationships may be modelled completely differently in either case.