Don't expect to get a complete answer from someone who just post few words here, if you are really interested in getting a unbiased view, go to www.theserverside.com and search ibatis, vs. jdo vs. hibernate.spend hours to read thru. Or take a look at jpetstore 2.X using ibatis,unlike 1.x it's provide more stuff than just struts. Keep in mind jdo in theory is a interface, implementations varies. Good news either JDO vendors, or hibernate guys follow the the same non-invasive principle in their PM, so until you start really serious development work,you can easily switch back and force without much impact to your domain model.
I am start to feel that within few years PM will become commodity like today's RDBMS, time to move on for something else.