Johnny here at WH has used an Atomic on his for several years now and absolutely loves it!
Once he got it dialed in (took about a week of trial and error testing) he literally has not touched it since. Fires right up, drives to the trails, wheels for the weekend, then back home.
Never a hitch.
We sold quite a few at $2400 bucks, before the FiTech came out with their competing unit at less than half the price.
If my memory's accounting is accurate, the Atomic never had any more, or fewer complaints than literally every other type and brand of EFI installed on Broncos. Aftermarket or factory Ford.
And among those, I think many here will agree that at least a majority of the issues with most are due to the install, and/or the general condition of vehicle's electrical system. Not including the FiTech FCC debacle that is.%)
The remaining issues are with sensors, compatibility with ignition systems, troublesome initial settings, reliability with the included tuners, etc. Most of which are handled pretty quickly by most manufacturers. To the original purchaser at least.
I don't remember any more trouble with the atomic than any of the others. The main reason you don't see them sold and talked about as often these days is the release of the FiTech and Holley Sniper systems, that were literally half the price of the original Atomic price, pretty much put the choke hold on any of the higher priced setups.
Now that it's more closely aligned price-wise, you may hear more about them. But FiTech especially really got a foothold on the market when they released their sub-$1000 systems and it takes time to recover from a beat down like that.
Hard to relinquish that foothold, but markets like this are notoriously fickle and changing.
Paul