Steve, I have had terrible problems since moving to Leopard – and once you do it, its impossible to go back with the same projects.
Both AJA and Apple have replicated the Leopard-FCP-Motion Templates problem, but have not found the bug yet as it only happens on some systems, mine being one.
I have to use Motion as a 3rd party application, render 32 bit MOV’s and import them to FCP manually… very time consuming.
If you dont have that specific problem, i would say Leopard is fine, if you do, go back to Tiger before converting your projects to the new format.
Mark.