This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
I don't know of a comparison list anywhere - any such list is likely to be highly debatable, as any "technology A is better than technology B" tends to be. Your best bet is to google for ORM and have a read of what is said about the various choices you get back.
If you aren't currently using any ORM package, then I'd start by looking into JPA, which is the JEE standard for this. There are several implementations for it out there, including Hibernate, OpenJPA and EclipseLink.