hmmmn, The thing I find with all Polys is that when hit them in the sweet spot, they are really sweet. Crisp and powerful....and ALU is one of the sweetest.
When you go off-centre, or when they start to go dead, that's where the harsh feel is really accentuated.
In general though, I find that ALU is harsher than Ace. I'm sure it has a lot to do with both the gauge and the composition of the string. Harsher is probably not the right word....stiffer, firmer is more apt.
Ace has a great soft feel that I haven't felt in any other poly.