[eluser]WanWizard[/eluser]
In larger (up to you to define this) applications, I find that using an ORM saves time when building the application (most standard model methods are already present), and saves time when modifying the application (maintenance). Especially if you're not the writer of the application.
In commercial ventures, time == money, so faster development gives you a competitive edge.
On the downside, every abstraction layer adds processing time, and will make your application a bit slower. Again, in most commercial environments, the time (and thus money) saved on developers greatly outweights the cost of an extra CPU.
And don't forget, there's quite a bit of difference between the ORM's out there, both in terms of functionality and complexiity, and in performance. I haven't tested the latest Doctrine, but the 1.x was slow as hell... I suggest you test some and use the one you're comfortable with.
