Updated my web server with Ruby Enterprise Edition 1.8.6-20080810 and Phusion Passenger 2.0.3 successfully. Both releases feature bugfixes for security issues and the like. My web server currently powers this blog, a Redmine instance for my own projects, and some “production” servers for a few Rails apps I’m writing right now.
I’d highly recommend Passenger and RubyEnt for low-volume or even high-traffic production Rails servers. It has greatly simplified my deployment and performance on a VPS with, say, 540MB of RAM is stellar. If you set the idle timeout to something huge, you can get almost Nginx+Mongrel/Thin level performance even on a low-traffic server; otherwise you have to wait a brief time (10-15 seconds) when the app has been idle for a while.