For valve covers get the Ford Explorer gaskets. They're metal reinforced and will last forever unless you screw one up. I can't say much on the EFI gaskets.
I like the reusable VC gaskets with the metal reinforcement. I usually just get the felpro intake pack with the upper to lower gasket... I have 5-8 laying around, I usually reuse the same gasket everytime.
just ask the parts stores for a reuseable valve cover gasket, the fel pros are the color blue.
for a set of VC gaskets they are pricey but are WELL WORTH it, they seal perfect with no sealer, and can be reused over and over again. i have had my VC off a number of times and just a simple wipe off and the gaskets are ready to be used again.
and alot of times the upper/lower gasket sticks to the lower and you can just reuse it. unless its a cheap paper gasket then it will probably tear and need replaced.