There are certinly alot of things I like about all 3 of these boats and they are different enough that at times I've kept all 3 in my fleet (although currently I only have an Everest). I also wrote reviews of each of these boats when they came out so here are a few links to those reviews.

2010 L-Burn: http://granolapaddler.blogspot.com/2010/09/review-2010-pyranha-burn.html

L-Karnali: http://granolapaddler.blogspot.com/2009/03/large-karnali-review.html

Everest: http://granolapaddler.blogspot.com/2007/12/pyranha-everest-review.html

The Everest is my favorite of the 3. Alot of that might be because it handles my weight best, but I also like its edge and the extra stern volume. The things I like most about the Karnali is the speed, ease of rolling, and the forgivness of the chines in low volume creeking. However, because I paddle a boat with more of an edge most of the time, I sometimes feel like I can get pushed around in the Karnali in higher volume situations. The L-Burn is similer in design to the Everest, but with less overall volume and less stern volume it is more playful for me then the other two (but at my weight I couldn't overnight in it). It surfs, spins, enders and even wavewheels in the right spots (I've never wavewheeled the Everest, anywhere).

I'll stop my ramblings now. Hope this was somewhat helpful. I'm looking forward to getting myself into a Large Shiva to figure out what its all about!

-adam
Team Pyranha