I have an NGP also and I like it but I like the Pixelskin HD better because it's a little less bulky. It definitely clicks when I squeeze it though, almost like the case is too loose and I have to squeeze it so that it locks into place.
None of you guys with the "old" version of the HD feel or hear clicking when you squeeze the sides of your phone? Try squeezing up and down either side of your phone and tell me if you notice that.
I've been noticing that too. It's not really too big of a deal for me, though.