Greeble is a framework for developing rich web applications.
PHPwnage is a forum and in-place CMS.
They're not in the same race.
Also, Rob has said many times that Greeble is targeted at developers and people who will know what they're doing - it's not made for easy, in-place editing. Right now, Greeble's built-in forum system is non-functioning and most everything you would want to do takes manual edits to the MySQL tables. PHPwnage, on the other hand, was designed from the beginning (Back in 2007) to be functional first, secure second, and well-written and expandable third, so far I've accomplished the first two, so I'm working on the third. Greeble was designed in the opposite direction: Make really good code with really good methodologies, then make it secure, then make it into something that works. Rob has also pretty much completed his first two, and is now working on his third. The difference here? While PHPwnage started out as a horrible, but working product, Greeble is starting out as a non-functioning secure prototype that no one could use. When we both get all three pieces done, we'll see where things go.
tl;dr version:
I followed a brute-force coding method with PHPwnage, creating a working product and then patching it and making it more useful; Rob followed a more methodical approach with Greeble, creating an expandable and secure product, and is now making it work.
Quite seriously tl;dr version of entire post:
Both.







Bookmarks