Choosy doesn't seem to work with Fluid sites.
I use Fluid to make browsers for certain webpages, including Google.com. If no browsers are open and I need to quickly search for something, I can open it instead of a regular browser without having to wait for all its tabs to load.
But when search results are returned, none of the links can be opened in the Fluid window. The Choosy window pops up, I choose the Fluid browser - the page flashes and nothing happens.
Earlier Safari was closed when I tried this several times and something very erratic occurred: I chose Fluid, but It appeared as though Safari was opening - all its tabs began to appear but never loaded and the entire window kept flashing rapidly, then after about 5 seconds it quit and Safari was still closed and I was back where I started from.