Yeah I usually do my own custom scripts, if you know how to code you can make faster and easier systems.
I use WP sometimes to create a simple cms - easier and quicker to do than building from ground up since I just fillet all the crap aout of wp and some skin I pick.
But in terms of speed you can't beat one of my flat file databases cms. They'll kill joomla, wordpress, drupal any anything else you want to throw at it. They're faster, they can handle more users, they can run on any server even shared with the digg effect and massive traffic.
Learn to code - it's worth it!