There is no denying the popularity and in turn richness of WordPress.
It is the only Wiki/Blog software with professional looking themes and a strong community of exports who can customize WordPress.
Requirements
- Allows multiple sites
Research
Multiple Sites
Start of multiple blogs instructions states that,
If you want multiple blogs using WordPress, you must actually install each separately (that is, as a separate WordPress installation). You can do this whether you have the ability to create multiple databases or are limited to a single database.
Please note in WordPress 3.0 there is now a native ability to create multiple blogs, referred to as a network of sites. This is because the codebase for WordPressMU was merged into core. See Create A Network.
Now, which method is better?
References
Determine if this actually increases security - http://www.suphp.org/Home.html. It seems to make the most sense for shared hosting.
This article indicates that suphp is slow as it makes php run as a cgi. Instead it recommends restrictions using mod_php - http://serverfault.com/questions/279938/should-i-use-suphp-or-mod-php-for-shared-hosting. Along this thread another poster recommends, http://mpm-itk.sesse.net/ which allows vhosts to be run under different uid and gid.
This restricts the php process to specific directories - http://help.godaddy.com/article/1616