I gave up on ORMs after a year or so (back around 2006) of ActiveRecord doing the "makes the easy even easier, makes the hard impossible" syndrome someone else mentioned.
Then a couple of years ago, I started playing with a DataMapper/Unit-of-Work ORM (Doctrine2, in PHP-land). My experience, writing a moderately sized warehouse-management application, has been very good.
In Doctrine, you don't write your schema/DDL. Doctrine does, based on your Entity and Association mapping. You write plain-old-PHP-objects, and then map their relations (in XML, annotations, or YAML). Doctrine reads and validates your data model, and generates DDL statements to create the schema. Big surprise: it creates pretty much exactly the same schema you'd expect. (And it will generate and manage migrations, too)
Unit of Work is a powerful pattern, too, especially for web apps. You just worry about updating entities in memory. The ORM then flushes them to the datastore in a single transaction at the end of the request (so, by default, you have a one-to-one mapping between http requests and transactions in the RDBMS).
Datamapper/UoW is probably overkill for CRUD stuff; that's where ActiveRecord shines. But it pays dividends when you're dealing with more complicated state-transitions on your underlying entities, and there are lots of cross-cutting concerns.