I love my P3's (178)... stiffer than almost any other park ski I've ridden (sans the Elan Mo2) but if you push them too hard, the tip will eventually fold in mid turn... Even though the tips are stiff, there seems to be a flex point just in front of the binding. (I mounted them at +2.5)
But still, they initiate and hold a turn really well, so much better than PE's
They've been bombproof for me, I've had tons of landing on ice on the east coast, and they still look new.
I haven't used them on rails though, so I can't comment on that.
I picked up a pair of 184cm P3's that I'm going to mount at recomended, I expect them to perform even better for all mountain.