Well, there was a very long discussion between Jason and me, but it's not something I'm going to share publicly.
Final conclusion on my part was that
for the 1911, the mag well makes a very real difference in my reloads. Jason generously sent me a standard MSH assembly so I could do a side-by-side comparison and it was no contest. No amount of taper inside the gun was going to achieve what that mag chute accomplishes.
I cannot really compare concealability since the only 1911 I've ever carried has one... though I can say I don't find it an issue in terms of printing.
For double stack guns, I've never found a mag funnel particularly useful because you're inserting the narrow top end of the mag into a hole big enough for the wide body of the mag. Then again, I'm not doing 1-second reloads. Adding substantially to the width of a double stack's grip
does have real concealability implications, so the trade-off isn't worth it to me.