Del Vento Switched on Bach by Wendy Carlos has been my main and only inspiration behind all of my Bach synth arrangements on my YouTube 🙂 My interest in synths started with Wendy Carlos and my very first synth was Moog Model 15 app for iPhone/iPad which is an emulation of the same modular Moog synth Wendy Carlos used. Besides, it's great for novices to learn synth basics, with a great tutorial. I also think it's much easier to learn synth basics on a modular rather than on all the later prewired synths like Minimoog (and basically every other synth following the same layout, they are countless).
P.S. Not to start another mobile ecosystem war but the fact all great audio apps (synths, effects, DAW-s) are written only for iOS speaks for itself 🙂 There are now so many musicians using an iPad live and basically none using Android on stage 😉