Java Virtual Machines (JVM) and their performance comparison
The answer is very hard, considering each JVM has different strengths and weaknesses.
I would look to the SPEC benchmarks - SPECjbb2005 & SPECjEnterprise2010 - they are current, peer reviewed and actively run by many companies (unlike the jmob.ow2.org benches, which were vaguely current in the Pentium 3 era!).