I still consider timthumb.php to represent an inherent risk due to the way that it operates. As far as I know, the following statement remains true:
NOTE: timthumb.php is inherently insecure because it relies on being able to write files into a directory that is accessible by people visiting your website. That’s never a good idea.
Without looking through the source directly, I see nothing in this list of TimThumb 2.0 enhancements that changes the fundamental functionality of the script. The enhancements provide some additional security-through-obscurity, but in reality, obscurity is not security.
Until I see objective evidence to the contrary, I stand by my admonition to use the core image-resizing and post thumbnail functionality only and always.