All the ones you mentioned are great boards. I ride a 2009 Gnu Street 157 - best board I've ever had for sure! I LOVE it!! (previous boards: Captia Horrorscope, Capita Indoor Survival, Burton G-Twin, Ride Control, Rome Agent) Not to say that those previous boards weren't good, but this one is just fuckin rad.
SO MUCH FUN to ride the Gnu Street! I don't care if they market it as a street board - to me this board is all mountain. SUPER SOFT (I compared it to my friend's 150cm Rome Artifact and that seems like a stiff plank compared to mine), easy maneuverability / playful, and the best part is that this board absolutely SLAYS the pow!
I've never rode the K2 Jibpan but I'd really like to try it out.
I love my GNU Street.