I have some intermediate layer data services (accessing backend systems) that will be shared by separate portlet applications. I'm looking to whether Portlet Service or shared JAR (in EAR or WAR) should be used.

One of the factors being considered is the administrative overhead caused by the two approaches. Another is about using container transactions and WAS dynamic cache. InfoCenter doesn't talk much about the pros and cons of using Portlet Service over a shared JAR file.

Would appreciate any comments on the following:
{code}1. Are Shared JARs a better solution performance wide?
2. Which is easier to manage with regard to deployment and maintenance?
3. If transactional behavior is expected within the data services, which of the approaches is better suited?{code}

Thanks in adv