I have seen them both! I own one the Phaze II. Undrilled.
From what I have seen in many different hands the Code X seems to be a very matched up ball for all sorts of styles, from crankrs to strokers. Very squared up to the pocket for many styles while dull. Many liken to the Vertigo but though the Vertigo was great it seems the CodeX might even be a smidge greater
The Phase II on the other hand seems to be strong cover ball with speed dominant players being able to fight off the cover...just what my eyes seem to see.
The Phaze II core is not flippy and the ball seems to only really get flippy when one goes to rev heavy speed soft mode like Jason Belmonte seems to do with this ball.
I am still backing off drilling mine,,,as I am that soft speed guy.
Both very good balls just some observed differences.
Regards,
Luckylefty