This is really interesting to me, because one of the key differences in the "feel" between iOS and Android is the touch "dead-zone"; Android's is larger, iOS' is nearly non-existent, and this often serves to make Android feel less responsive than iOS.

It's very curious that something like this could slip through into OS X given Apple's fanatical attention to detail, and the fact that they're aware of what that delay means for mobile UX.