Here are the slides to an interesting talk about PHP frameworks, given by the "first" creator of PHP, Rasmus Lerdorf, who now works for Yahoo.
In PHP 3.0+, Rasmus kind of gave up control of PHP to a couple other guys who took it in much more of a Object-oriented way. I like the following slides where Rasmus questions how 10 years of OO haven't added much (except confusion) to the language :
http://talks.php.net/show/drupal08/4 PHP 1995 - short and simple
http://talks.php.net/show/drupal08/5 PHP 2005 - after 10 years of OO cruft added
Anyway, Rasmus later gets into analyzing performance, and winds up comparing various PHP frameworks. Rasmus is more of a C hacker than a language designer, and performance is one of his specialties.
The performance of "Hello world" in various frameworks are compared starting here :
http://talks.php.net/show/drupal08/25
Here are some of the highlights :
CakePHP 25 trans/sec Symfony 100 trans/sec Zend 125 trans/sec CodeIgniter 305 trans/sec
CodeIgniter is far and away the fastest, at least in this out-of-box "Hello world" test. Speed of course matters for Rasmus and Yahoo. A 10x speedup for Yahoo means buying 10 times fewer servers (and 10x fewer sys admins).
But I like CodeIgniter for a few other reasons :
- Good documentation
- Runs on PHP 4.3.2+ (important for legacy systems)
- More flexible and fewer dependencies than say Symfony or CakePHP
The various PHP frameworks have pluses and minuses, but I'd look at http://codeigniter.com/ if you're looking a a framework.