I've got the generic man made stiff foam "cork" tape on a lot of my commuters. One of them has had the same tape on it now for well over 10 years and it's still fine.

When I recently switched my single speed over to moustache bars a few weeks back I replaced the 7 to 8 year old foam "cork" tape with new stuff. Not because it was worn but because the tape on that bike is white to match the steering head color and it was a little stained and dirty from age. But it functioned just fine.

I like the foam "cork" tape for the cushioning I get from it as well as the increased size of the grip that helps spread out the pressure on my palms.