My understanding from people who have done per cylinder O2 monitoring is the modern TBI fuel distribution problem is because the fuel is injected right into the plenum, and gets the full air distribution issues every intake manifold has. The old GM and other OE TBI's had the injector above the throttle blades which mixed the fuel into the air more evenly as it passed by the blades. Even when you can see fuel puddling up on the blades at part throttle! Basically equivalent to a carb.
I have not seen tests of the MSD Atomic unit, but the injectors are above the throttle blades so I'm assuming better fuel distribution.
