Limonade (<a href="https://github.com/sofadesign/limonade" rel="nofollow">https://github.com/sofadesign/limonade</a>)<p>The advantage of using Silex is that its from the makers of Symfony(Framework). So it uses alot of the budles/components from there, Eg: Twig Templates...
Slim (<a href="http://www.slimframework.com/" rel="nofollow">http://www.slimframework.com/</a>) is built around modern features of PHP 5.3/5.4 like closures and is similar to Sinatra/Express.js