I'm pretty nerdy. I set as a threshold for the site anything I deem too nerdy for me, as being too nerdy in general. APG Composer very nearly was dismissed as such. This 3 Voice FM Synth is very nerdy, but it is free so I poked around with it for a bit on your behalf. I wouldn't recommend this to everyone, but it is definitely worth checking out if you like to seriously geek out with some knobs and synthesis.
There's no Audio Copy here, hell there isn't even exporting, nor MIDI, nor any of the usual stuff we expect, but it is kind of awesome at what it does.
This is really just a tech demo for the company's Audio Plugin Generator, software for designing VSTs, but that is also interesting as they were able to port it to iOS without any code changes. We could be seeing the Reaktor of iOS that many synth nerds have been dreaming of.
Here's a track I put together in the first 20 minutes of playing with it. I like the results! Just slap some drums on this and it's a solid track.Thanks to iDesignSound for bringing this to my attention!