Used to be true, but not so anymore. Improvements to their engines and transmissions means the US Army machines now have about the same power output as the UK aircraft.
So I've found out after a bit of research, but my information source was somebody who flew the thing, while I was sitting in the rear cockpit of one 4 years ago.
You're so so wrong. The AH-64E (Block III) will be light years ahead of the WAH-64D (Block 1-standard) Apaches we currently operate in any differentiator you wish to choose.
On the Avionics I would agree with you, after again doing a bit of googling (my comment was based on the engines and transmission side of things), but that is hardly surprising seeing that I bet quite a bit of that technology going into the 64E was originally developed for the RAH-66.