I have had both.
Peppermints are the devil.
I know some will disagree, but I can say from 1st, 2nd, 3rd etc hand experience, MOST peppermints will indeed eat Aptasia, and when they run out of Aptasia, they will start in on any LPS they can find starting with Acans. In have had them absolutely destroy some massive acan colonies as well as Torches and Euphillia.
The tank I had them in, thankfully relatively small at 60 gallons, didn't have any SPS so I have no personal experience there.
I went so far as tearing the tank apart to get the little devils out.. Then fed them to my Harlequin Tusk.... Who was then happy... As was I...
Peppermints are the devil... Consider yourself warned.