[eluser]Xeoncross[/eluser]
Codeignter is great for rendering non-browser based views like XML and JSON because unlike other Frameworks and ALL CMS's - there is no default layout file or anything that the $content is placed into. CI comes out of the box ready for only sending data that is NOT to be placed within a main layout file.
Also, as far as speed:
From my research I dropped Zend framework because CI was 3x faster.
With a couple core hacks you can disable some of the more useless stuff like URI routing and things if this is just a hidden request thing from a desktop.
