There has been a lot of buzz over Sun hiring Charles Oliver Nutter and Thomas Enebo (two core JRuby developers). Certainly a fine thing for people who use both Java and Ruby. My hope is that they do a lot of work on Tomcat/WEBrick/Rails integration for hybrid JSP/Rails web apps.
I have been using both Ruby and Rails a lot in the last year, and have not missed Java too much. That said, an efficient Rails platform on top of a Hotspot JVM sounds good. My quick experiments with JRuby have not been totally without problems, but with Sun's obvious motivation to get a first rate Ruby environment running on the JVM, I expect things to get better. The smooth integration of Java classes in an interactive Ruby IRB shell environment is fun.