I have seen this product and me personaly wasnt impressed. Before Godox AD200 this would be amazing thing, but nowdays 1 AD200 is both strobe and speedlite, does all that this magmod modifier does, but cheaper and better, because you can use S-bracket to attach other modifiers like real softbox umbrellas and list goes on and on. Also keep in mind that AD200 with s- bracket, lightstand and godox modifier (either softbox, octabox, umbrella or even beauty dish) is actually cheaper then single 600EX or SB910.
Now im not brand bound or Godox fanboi, but im talking from price and practicality standpoint.
Magmod is too late and also really expensive for what its offering.