Download Chrome beta with Retina support (code name Canary) from Google Tools.
While Safari 6 problems on Retina Macbook Pro solutions are being found, Chrome beta with Retina display support can be an alternate solution, albeit with its own set of problems.
Google Chrome Retina support
Stuttering, flashing, missing page parts, delayed typing/keyboard reaction, character corruption are Safari problems (Safari version 6) seen under Mountain Lion (OS X 10.8) on Macbook Pro Retina. The current Safari 6 version 8536.25 (check in the menu bar by clicking Safari –> About Safari) seems to only have serious issues on Macbook Pro Retina, not on other Macbook’s like the Macbook Air.
Here are some forum threads where others have noted the same Mac Safari problems
Here are some visuals of issues: