The old optical drive was making awful, awful sounds and would work only rarely.
The repair went very smoothly. Some of the steps were a little trickier than I'd expected. It was more difficult to detach some of the cable than it seemed they should be. But for the most part it was good. No big surprises.
I should have read all the comments before I started. There were a few that would have made me more careful on a few steps, and a few that might have made me try a simpler approach on a different step.