TX is easier to fiddle with, when the stocks off its basically one bolt to take the thing to bits. Its also running on synthetic bearings to start with (ie tuned out of the box).
I find the trigger easier to reach on the TX out of the box, HW's tend to need a set back blade to suit my hands.
I've never noticed POA changes with position, with the exception of prone (which i'm pants at to be fair). Thats with the standard stock, and a modified stock.
I've had a Mk2, and 2 MK3 HC's, all lovely.