After my successful Windows 8 installation just minutes ago, the first thing I checked was its compatibility with Legacy Family Tree. It runs perfectly! No problems at all.
I can launch Legacy from the normal desktop mode, or from Windows 8's new Tile Mode. Here is what it looks like:
I have not yet done any customization. On the left are the default tiles, and on the right are my most popular apps/programs. Clicking once on the Legacy icon, Legacy opened as expected.
This is going to be fun! I'll keep you posted on what I learn.