I don't have a stake in the Ruby webserver wars, but the unicorn site has a very good discussion about how it works internally, why it's build as it is, pros &

I don't have a stake in the Ruby webserver wars, but the unicorn site has a very good discussion about how it works internally, why it's build as it is, pros & cons etc.. This seems to be missing from most of these project sites, which are often just marketing (look! It's better!!), and therefore not very trustworthy. From the outside it looks like the biggest differentiator in each generation of ruby servers (and, I guess, db managment systems :) is not that the new is better or worse, but simply that has different trade-offs.