For curiosity’s sake, I checked and the current retail price for Audulus on the Mac is $49.99 and Max is $399, so by my calculations that makes Max 8 times more expensive. Given the difference in price, it’s not surprising that Max offers more functionality. As @biminiroad points out, Audulus is available on iOS which brings some constraints on functionality compared to software running on a Mac/PC. An external API is one of the features that’s not really possible in an iOS environment. Apple requires that any executable code installed on an iOS device be signed by the developer with an Apple provided certificate and the only approved installation mechanism for executable code is via the App Store. While not as restrictive as iOS, software marketed via the Mac app store is also subject to certain constraints. As a programmer, I would love to have the ability to extend Audulus, but I don’t see any practical way to implement this within the iOS or Mac environment. While I would agree that Max offers features not available in Audulus, I would argue that Audulus still represents better value for the price.