I needed to get rid of Timthumb in all my themes and needed to use WP's image resizer instead. I also needed to use some of Timthumb's filters but the currently WP's Image Editor classes don't support them. So I created my own! I wanted it to be secure, to be of similar usage, faster and most of all utilize WP's Image Editor classes.
BFI_Thumb has a few filters now aside from WP's rotate, crop and rotate: grayscale, colorize, opacity, negate.