When I wrote SQLAlchemy, a key intent was as a working rebuttal to the "ORM is vietnam" argument. (edit: for those who don't know where that phrase originates, it starts with this very famous post.)
This was achieved by: a. tweaking the key assumption that relational concepts must be hidden. They don't. Practicality beats purity.
And b. not underestimating the task, i.e. unit of work, cached collections and associations backed by eager loading (solving N+1 problem).
Hibernate does both, but suffers from the limitations of Java - complex, heavyhanded. Python is what makes SQLAlchemy possible.
Our users can now write super-SQL-fluent apps succinctly and quickly; that's all the proof one should need that ORM is definitely worth it.