Help with Social Networking Portal

[paganwinter]

Hi, I am building a Social Networking portal and would like to know certain things before going ahead.

I know a lot of platforms, CMSs and Engines are freely available that can be customized.

But what I'd like to know is which of these is better suited for a Social networking portal which would also have Gaming elements in it? The following are the things that I have tried out:

 

CMS:

Joomla

Drupal

 

Social Networking Engines:

Elgg

PHPIzabi

 

PHP Frameworks:

CakePHP

CodeIgniter

Symphony

Zend

 

 

Of these, which would be best for ease of use, ease in customizing, Scalability, Security, Robustness?

Is it a good practice to use readily available engines or is it better to learn from those and try to build one your own using any of the PHP Frameworks?

 

Thanks in anticipation...