It's the only client that has the 'Protocol Header Encrypt' option which is very useful for those of us who's ISP's use services like P-Cube software. The P-Cube service engines are VERY capable of doing IP selective throttling and BitComet is the only solution I've found that can has an option that can get around it.

Like a 16mhz chip in those suckers, wicked fast. But hey, they're still fun as hell in my opinion