You are not wrong! A friend and I have the identical same plane. He runs an MAS K-series on his and I run a MAS Scimitar. Although they fly at almost exactly the same speed (mine's a little faster), his just gives the impression of being *much* faster -- all because of the howl that the prop creates.

Spectators (and fellow fliers) love it.

The MAS/APC debate isn't really that important. Most of today's engines have more than enough power for the airframes they're attached to so it becomes an issue of wallet-size and personal preference ahead of raw performance.