Ask HN: Is anyone running Ruby 1.9 in Production?

I have a Rails game (www.forumwarz.com) that's moderately popular. Right now it's running on Ruby 1.8. It's holding up well with our current load (about 2M dynamic requests/day), but we are in between episodes of the game. Soon, we will launch our third episode and expect a large spike in traffic. We plan on adding another server to our pool, but it occurs to me that Ruby 1.9.1 might be a good idea too. After a day or two of tweaking, I seem to have the app running on Ruby 1.9.1 in my development environment. Early benchmarks show that it's 3x as fast as the Ruby 1.8 version, which is quite promising. I am curious as to whether anyone running a similar or larger Rails site are running Ruby 1.9.1? Is it stable enough for a production app? What are your experiences? Is there anything I should watch out for?