G,
Popularity, Maybe?
I've swapped out a few Mallory setups for MSDs myself, and never had any problems since. I use to run Mallory on a number of prior vintage Camaro builds and it worked okay. Note: ERA installs MSD from the factory, with the MSD power box mounted under the glovebox as an option. Works great.
Here is an old thread right here on ClubCobra a few years back with some other experiences with the Mallory stuff.
Mallory, ignition problems, and my last good nerve