Nothing. I looked at KISSMetrics ages ago when the private beta was first leaked. Similar to crazyegg it focuses on a single aspect of analytics, in this case conversion funnels. So it is simple to setup funnels for every possible conversion point (which if your website is effective should be almost every page). However, you can do this on GA too, which is also a hugely more powerful and integrated tool. Someone mentioned previously how expensive enterprise analytics is... this is _not_ enterprise analytics. I'm really not sure who they're aiming this product at.