I've only used CakePhp in anger over a period of several years. Yes, it is big and may seem bloated but, to be honest, I think that if I had used any other framework it would be as big by the time I've added everything that I have and use with Cake.
Speed-wise, we're talking small fractions of seconds difference between the contenders. Optimizing your site using tools like Yslow and gzip and, of course, sensible design, will realize greater improvements than the choice of framework.
http://www.grasset.es is a site I built about 4 years ago with Cake. It's big and complex, but I don't think it's slow.
