The apc tends to be a more high performance prop and the master airscrew more durable.When i first started flying and was scraping the prop alot on landings..i tended to like the ma prop becasue you could scrape the ground and not break it..however now that i would rather have the performance out of a prop a graupner or apc is what i prefer.I find the ma props tend to flex to much and although they are still fine to use the apc is better. The other side of the coin however is that in scale applications such as a war bird the ma prop looks more scale..Kieth