I rode a 162 Heritage so my flex experience will differ than if comparing a Heritage and Cobra of equivalent size.
I found the 162 Heritage to be quite a bit stiffer than the Cobra and also noticeably more damp. I weigh around 180 to give you an idea of where I'm coming from.
In equal size, I'm pretty sure the Heritage is still going to be stiffer and more damp. This is not to say the Cobra is super lively and flexy as it isn't that.
I saw your comments in wolfie's thread. Your style indicates the Cobra as being the better option for both pow riding and with a little playfulness mixed in. The Cobra was also a dream to ride in the trees with pow. It allows you to paint brush turns effortlessly which is very handy when navigating trees. It was also great for navigating moguls.
Normally, you'll catch me on the Evo for tree and mogul riding because of the soft torsional flex. Even though the Cobra isn't torsionally soft, the board by design turns great.
The only downside to this shape is that it works against you when in switch mode. It's not horrible as long as you aren't trying to tackle big lines entirely switch. It's also much less of a problem if you have experience riding true directional boards switch.
I'm up in the air on these two boards. I may just try to demo them next season. I'm right up there at about 180 as well. 5'7" 9.5 boot
My thing is even though I do carry two boards when I go out west I end up riding the longer board just because I like the speed and am most never on trail because I'm looking for powder or in the trees but I always end up in areas that are just fun to screw around and throw myself off of anything and everything I see. I just started to notice more about the altered genetics on my last trip and realized I really wasn't able to hold my speed and plow through crusty shit with it. So now I'm hellbent on getting something to replace it for big mountain!