In this presentation from QCon San Francisco 2008, Jason Seifer takes a look at the different Ruby virtual machines (JRuby, MagLev, IronRuby, Rubinius, MacRuby) and how to choose what fits best within the enterprise.
Jason takes a close look at all the alternative Ruby implementations that are currently being worked on. Complete with a overview of the current state ("current" being the state in November 2008), every Ruby implementation is flagged with a "Yes" or "No" recommendation.
Watch Jason Seifer's "Ruby VMs: A Comparison".
InfoQ Homepage News Presentation: Ruby VMs: A Comparison