I had never considered my MC startup times satifactory, but I always thought that was the price one pays for a program with so many creeping features. But recent discussions of startup times have made me realize that (once again) I am a statistical outlier. People talking about 1- or 3-second start times, whereas I was glad to see MC go from ~20 seconds down to 7. It turns out that it was entirely due to the complexity of my defualt view.
Today I tried loading my ~20,000 track audio library with a default Artist/Album view. This replacing the 8-pane expression-laden pane setup I've been using. My start time went from 7-seconds to somewhere south of 1/2 second. I would call it neck-snappingly fast, and I've still got 29 columns in this view. 1/2 second for 29 columns. It was all the panes that were slowing me down.
Now that it's so easy to add or edit panes (but not yet move them), I'm going to a much sparser setup, pane-wise. And I take back all previous grumblings about slow startup. How in the world jriver gets this much complexity to load so fast I will never figure out. But my sincere thanks to the ingenuity of the jriver crew.