I'm assuming you mean the MSD Atomic? I looked at that when I was deciding on an EFI solution and there were several reasons that I decided against it.
1) It was, at the time, much more expensive. I have no idea how the price compares now.
2) I didn't like the idea of having an external ECU. Another box to mount somewhere didn't appeal to me.
3) The fitech that I wound up with also has a handheld controller. The sniper does as well, but Holley hadn't come out with the sniper yet at the time
4) I had bought an MSD transmission controller for my 4R70W transmission and it never worked correctly. It absolutely would not read the range sensor, no matter what I did and when I tried to find support for the TCU there was none available, anywhere.
That last one was what soured me on anything MSD. I blew several hundred dollars on a trans controller that now sits in a box in my garage that neither MSD nor holley, their new owner, supports. I probably wouldn't use anything MSD if you gave it to me. If it works for you, that's great, and its awesome that it does, but you wouldn't catch me using one.
oops yes I meant MSD atomic. Long day at work. I appreciate your candor and totally respect your reasoning for not liking their products. I believe the pricing has come down since Holley has acquired them.
Whether things will work out for me in the end remains to be seen as the final product is a few weeks away.