As to which is "better," I'll let the tech analysts speak to that... BEA's content management isn't even mentioned in Forrester's Wave for ECM products:

http://www.oracle.com/corporate/analyst/reports/infrastructure/ocs/forrester-ecm-q42007.pdf

Nor does Gartner bother to estimate BEA's offering in their ECM "mystic grid":

http://mediaproducts.gartner.com/reprints/oracle/150426.html

That alone speaks volumes... odds are low that its suitable for managing more than small amounts of niche content, and it probably lacks features that most people expect in an ECM offering.

Now... is BEA sufficient? That's up to the customer to decide. Perhaps it is, perhaps it isn't... depends on the use case. However, if they want content management in more than just their app server (which is usually the case), then the odds are good that they would benefit from a broader solution set.

The primary value I see for BEA's content management is as a read-only cache for a centralized content repository (Stellent or otherwise). There's a lot of value in publishing content out to your app server... but you need to retain a "single source of truth" in your architecture. There are also some security gotchas, but those can be dealt with in multiple ways.