from what i've heard the comparison is more like this:
JK karma & Villain vs. LL Stomper/Jefe vs. WS Habitat/Recon Vs. Pyranha Burn/Shiva vs Dagger Nomad/mamba creeker
JK Zen Vs . Remix vs. mamba vs. Ammo
SuperHero is an awesome micro creeking/riverrunning boat comparable to the WS Diesel and maybe the Pyrhana Ammo but higher volume.
I own a SH and love it, but its not the 'big water/waterfall boat' unless its your only creekboat...like in my case. and i dont run class V, but have had a blast on class III/IV creeks and rivers. it also rolls like a champ and turns on a dime. it even surfs well. JK creekers have the anti-shock bulkhead that is a cool feature as well. BUT some people hate the outfitting. I find it works great for me, and is more comfortable then any other brand i've owned. (can stay exponetially longer in the JK boats before my legs go numb.)
one more thing i discovered this summer is that the superhero packs up really well for self support. tons of room for drybags in the bow and stern, and the bulkhead slides in and out on a track really easily for ease of packing the bow. 95 gallons is a big boat. that still paddles
I have heard really good things about the JK Karma from their team at paddlefest in Colorado...fast/stable/ good rocker for resurfacing etc...(granted they are in the biz of selling their newest boats, but they were all genuinely excited about the performance.and gave examples of how fast it is downriver like Dane JK winning the Grand Prix in Chile in the Karma etc... ( taken with a grain of salt since the kid is killing it in any comp he enters.....)
I am not any sort of expert, and totally biased to JK boats so i wont even try to opine on the other boats, but that should give you something to think about....