I've used MSD race boxes, 4040B,404C,MSD7,7A, 7AL2 and now have a grid that I have not used yet.
I had one 7C box fail years ago at the Mopar race in Las Vegas, it ran fine and then quit
I sent it back to MSD before they got bought out and they told me they couldn't fix it due to not having a correct harness for inside the box Me thinks they wanted me to buy a new modern race box
I know bunch of NHRA racers that have used the race boxes since they came out, I don't remember any of them griping or complaining about them
I have two 7C and one 7AL2 boxes that I will continue to use in the future on motors needing them, same thing on the little red coils and the older Mallory/MSD race coils
I bought the grid to use with a future EFI build, I called MSD last year or the year before to ask them about using it with the 7AL2 box and they said it would work, I'm hoping their correct

I've also thought about using a coil on plug ignition for high compression race motor on E 85 but that may be overkill
I'm also looking at building a building a big C.I. Pro Charge motor that will make north of 2000 HP on E85, I will definitely use a grid on it to control the timing