I've paddled both boards and as far as an allrounder goes I think the PSH wins hands down.
As far as using these boards as down winding boards I think the Naish has too much rocker and too tippy unless you're a featherweight.
The PSH almost doesn't have enough rocker in the nose area (IMO) for down winders but it's stable enough and could be done.
I think the PSH would also work better in small waves because of the extra glide.
But if you're looking at big wave charging with late takeoffs and full rail digging bottom turns the Naish looks much more the right board.
There's no doubt that the PSH will also work in big waves and Blane and others has proven that.
When I paddled the PSH gun the other day I was surprised at just how stable it was..and how much glide that it had.. I wouldn't go as far as to say it's a big easy board with a gun shape..but it's something like that.
When I paddled the Naish gun in October last year I could hardly stand on the thing.. It was so narrow even tho 28" isn't all that narrow the full width is only for a very short section of the board and that narrow persian-slipper type nose sits way out of the water and the tail is also very narrow.
I had to kneel paddle it to get out and once standing the sweet spot to balance was so small.. But then I'm 90 kg..and not that good..

JB is my weight and he handled it ok...a lighter person would be fine I'm sure.
The PSH keeps its width for much longer.. The nose sits low and the tail is a bit wider so no wonder it's much more stable.
But here's the odd thing..
The Naish that I paddled was about 28" wide and only about 4" thick max.. I took a picture of the bottom of the Naish gun yesterday look what it said.
I didn't notice this till after looking at my pictures.. Maybe it's a typo error on the board.. It didn't seem that thick.
I'll have to check to make sure that's right because if Naish have changed the guns dimensions it should be much better for the average Joe.
I'm sure if Blane reads this I'm sure to cop a lashing but it's just what I think..and I'd be interested to hear what others think..
DJ