Recent work on the baseline compiler for faster bytecode implementations and bytecode merging show speed ups from a few percent to 5%. This performance matters as the baseline compiler is the baseline that the adaptive optimization system attempts to improve upon. For example, a 5% faster baseline compiler means that code needs to be hotter (say 5%) before the adaptive optimization system thinks its worth involving the heavy duty optimizing compiler. Early JVMs didn't provide adaptive optimization systems and so relied upon this performance. For more realistic benchmarking this performance is also important, as users notice start up costs whereas they may never appreciate the benefit of GC and compilers optimization algorithms.
Comparing performance with Jikes RVM shows MRP is now consistently faster, combined with the enabled execution of programs like SPECjvm2008 and ecj, numerous bug fixes, and of course execution on Windows, MRP is the metacircular development platform of choice.