Esqueleto and persistent are quite nice. Their one downside is SqlPersistT. The abstraction makes sense, but once you have people putting that thing as the base

Esqueleto and persistent are quite nice. Their one downside is SqlPersistT. The abstraction makes sense, but once you have people putting that thing as the base Monad in your stack, you're in trouble. Its nature means it holds a transaction (and therefore connection!) open during the entire action if used that way. This will cause big problems, like causing requests to queue on your connection pool if some other IO/parts of the code are slow and hogging the connection.