The question you pose just doesn't seem like a good question. IMHO
Any method (be it induction, flame or salt bath) can anneal the brass to the same hardness if the proper heat and time is used. As such, non are superior.
The real issue is controlling the temperature and time to get to the desired hardness. Put together the computer electronics that can control this quite preciely with speed of induction heating, then such a method would be superior in terms of timming and consistency over what is often done with the flame or salt bath method. You'll have to split hairs when the latter methods are used well and compared to how well the former does.
Annealing Made Perfect's testing, analysis and data makes a good case for annealing. But they didn't do a comparison with flame annealing to see what difference if any can be seen on target or even in terms of measuring difference(s) in hardness. IMHO, they didn't do so as I feel they can't show enough difference between the two methods, which would in all probability mitigate the annealing benefit of their product/system.
If I could find a significant difference in the annealing result for going with induction over flame, I'd change from flame. Though I'm not a metalurgist, some of my undersanding how such alloys work comes from having had some college physics and mostly having worked with and testing various aircraft alloys (having to do with work hardening due to vibration and/or repeated stressing). When I flame anneal my brass, I give a lot of attention to details and get pretty consistent results. . . which is what I'm after to get consistent neck tension and interference.
One optional method is no annealing at all, where one controls and minimizes the amount of work being done on the brass, by way of customizing sizing dies and chamber specs for a particular load and projectile.