quite a few newcomers come to rails and think it's slow, because they're 'doin it wrong'. every framework's speed is really about your deployment setup. running mongrel can be slow, especially if you're load-testing a single mongrel instance. multiple instances can be slow if they're connecting to a slow database and serving static files.<p>put nginx in front of thin, start caching frequently used objects, and slice up your database and suddenly speed isn't a problem. php has the (perceived) advantage of running compiled in an apache module, typically. but it's a perception -- you have to do a little more tuning with your rails deployment to make it scream, but make no mistake, it can scream, even under heavy load, and without a huge server farm, at least up to 500K pages/day. i know that number because i've served it. quickly.<p>in radiant. (gasp! yes, with some caching.)<p>with one database.<p>it's a lesson i learned working with tomcat back in the day: defaults suck. learn your framework, learn your app server, pick the Right Thing. it's all about application tuning and app-server choice, and that goes for every language and platform in existence.