Quoted from Parzival:
I've played the pro quite a bit on location, and am now dialed
in on hitting the magna-save (don't have any video however).
I kind of like the button location, as it makes you anticipate
more to use it. To be fair, I haven't played much of the previous
two BKs, but on SoR the magna-save bails me out at least one a
game. Even if it's not going to drain, getting a controlled shot
can be nice.
Same with me, I like the button location and successfully use it all the time now. Even saved two balls at once with it during multi ball, one over the magna save and the other was orbiting around it, looked pretty cool. Just like you I never used magna save much on the earlier black knight games for me mostly because I would always forget it was there. So personally I prefer the button where it is.