Hey folks, I've only recently started researching on RoR as a possible framework for a large scale website - the initial candidate was PHP which I know my way around - but the project being quite complex and extensive made me wonder if RoR wouldn't be better? My main preoccupation is speed and control, can RoR handle heavy loads? and will it give me as much control over the website as PHP?

The framework/language of choice would have to be fast enough to handle many users (like a forum), work well with AJAX, be as low-level as PHP, easy to maintain and upgrade. Can RoR handle more than the typical CMS?

examples would be www.last.fm or www.facebook.com

...And if I needed to embed C code, would that be possible? howbout interfacing with a PHP script?