head gaskets: copper or teflon???

[il-rigido]

I'm finishing the work on my 93CI new Shovelhead engine, and still don't know if to use copper or teflon Cylinder/Heads gasket.
Many people says copper is good but you have to use some kind of sealant as copper coat, teflom is surely simpler to use.
Personally I have used teflon gasket on my old 80CI engine without any kind of problem for years and years.
What to do?????
Why S&S gives copper gasket with Sidewinder kits??

[rosascycle]

Copper is the stronger of the two materials also because its a shovel head its EZ to re tighten head bolts after some run time we have used copper in shovels form 1975 and still use copper in my 15 to 1 compression shovel today