Write about what DM can do that were pain points in AR

[tpitale]

I remember switching from AR because of certain pain points, things solved by DM.

Properties in the model (so you don't have to keep checking the schema in the DB)
Better associations (through many, more than 1 step away)
Composite primary keys

Please comment with your pain points solved by DM.

[dkubb]

I like how DM uses the strengths of the DB rather than just viewing it as a dumb storage container. I mean, if server side constraints aren't being used, then there are alot faster/simpler ways to store objects in a datastore than an RDBMS. The strength of an RDBMS is that it does maintain consistency of the data it accepts, so that you can be sure that it represents true facts within it -- that you can trust the data it contains.