Works fine, but seems slower than it was in Snow Leopard. But maybe thats just because I have been using FCP X for sometime.
Not sure if it'll install from the disks, but it installs via terminal just fine (I've always installed FCP 7 from terminal so I didn't have to play "swap the disks" for 4 hours).
Also, I should mentioned that I am not a hardcore FCP user, I typically use Premiere Pro or Avid for editing just because I am more comfortable with those programs. Therefore, there may be some major compatibility issue that I am completely unaware of.