As noted on Andrew Spyker's blog, see how IBM WebSphere Application Server v6.1 leads both Oracle and BEA on per core application server performance.
"A powerful IT infrastructure is also required to support the growing number of transactions across the enterprise, as well as with customers, partners and suppliers. IBM recently beat competitors by 37 percent in an industry benchmark that measures high-volume transaction processing that are typical in today's customer environments. IBM WebSphere Application Server established record-breaking SPECjAppServer2004 benchmark performance and scalability results involved more than 15,500 concurrent clients and produced 1,197.51 SPECjAppServer2004 JOPS@Standard (jAppServer Operations Per Second), which translates into more than 4.3 million business transactions over the course of the benchmark's hour long runtime."
WebSphere Community Blog: http://webspherecommunity.blogspot.com/2007/10/websphere-beats-bea-and-oracle.html
IBM Press Release: http://www-03.ibm.com/press/us/en/pressrelease/22409.wss