According to Middleware company whitepaper http://java.sun.com/products/ejb/pdf/j2ee_dnabwp.pdf J2EE platform can easily be more scalable than COM+ one.
So, here is the question - how come there are no TPC-C results for any of the J2EE implementations(www.tpc.org)? Few months ago I saw results using WebSphere, but they are no longer there. Weblogic's license specifically prohibits publishing of any performance benchmarks. Why?
You might want to see what Roger sessions has to say on TPC and the middle-tier: