Ferret on a production site

Over the weekend we launched http://tourb.us, a social search site for
live music that makes heavy use of ferret. We’re using version 0.3.2
and have had very few problems so far. You can read about some of our
ferret usage here:
http://blog.tourb.us/archives/ferret-and-location-based-searches

I’d be very interested in hearing from other people who have ferret
running on a production site. How big are your indexes? Have you run
into any performance problems?

Thanks for some great software, David.
-gary