Definitely one of the best Keyhole images I have seen Mike. Awesome subtle details everywhere, and nice to see the small streaks of nebulosity around Eta itself.
I compared with my own hi-res image of the same area from a while ago, and I noticed that while I actually seem to have captured fainter stars you have a lot more contrast and definition in the nebula itself. I would assume this is because you've worked with the nebula separately and then added the stars back in the end? I haven't experimented with that yet, but it's probably about time
Congratulations on yet another beautiful image.