That is why they need an unbiased person to compare the boats.
What I've learned recently:
Mamba: lots of bow edge, and no stern edge. Seems a little harder to keep a line than average, and it does not sharply turn into eddies without forcing it to.
9R: Lot's of bow rocker, little in the stern. It stays on top of holes and boofs fairly easy, but the stern will bump stuff on boofs, and it likes to turn you up stream if you are not careful. I've heard the term "whippy" to describe this kayak.
Machno: Less edgy than a Burn, and more rocker on both ends. It boofs super easy without catching anything on the stern, it holds a line well, and has a good balance of stern and bow edges. It's the easiest kayak I've paddled to date.
The Nomad (new version): It's a tank, and one of the last displacement hauls. It's harder to initiate a turn, but it's not too bad. It boofs well, and the landings are much softer than anything else I've paddled. It punches holes well. It is very tough to hold an upstream angle when ferrying.
I'm liking the Machno the most, but the Nomad would be my choice if I hucked a lot of falls.
I really want to demo the Nirvana and Waka Tune and Gansta.