Three years ago the state was much worse, so I ended up writing my own ORM, which tries to address some of the issues pointed out here. My primary need was to

Three years ago the state was much worse, so I ended up writing my own ORM, which tries to address some of the issues pointed out here. My primary need was to be able to map the same models to different schemas, including very badly designed legacy ones, so the mapper layer had to be clearly separated from the model and very hackable. Also, the query syntax had to be powerful enough to avoid SQL whenever possible, so that the same queries could be applied to different environments. Right now it implements Units Of Work and Identity Mappers; it has deep querying and multilevel strategic loading (not limited to one level as with DataMapper); functions and aggregates; and many other features, wrapped in a familiar easy syntax. If someone wants to try it, I'd love to hear some feedback: it's at https://github.com/me/spider https://github.com/me/spider.