Don't know about the Blunt. I have the Skate Banana. It revolutionised my riding. (i.e. - doesn't suck) It is amazingly grippy on ice - there is no more effective grip technology than Mervin's.
What sort of park?? Big jumps maybe not either of the two you suggest. Jibbing and buttering are the Skate Banana's strong points. I thought the Evil Twin was a fair bit stiffer than the Skate Banana. For landing bigger jumps and a bit more all mountain freindly maybe the Evil Twin or something like the Never Summer Proto. The Never Summer Evo is a firm forum favourite (nice use of alliteration!) and awesome in the park flexier than the Skate Banana (if you were going for the 56)