Not only for its sound but for sound design possibilities and for being able to import sysex / patches being made for the Yamaha DX 7 Synthesizer,
it also comes with over a thousand patches-
just a keyboard with the patches would have been enough!
So it is an emulation of a digital synth and the sound has a digital feel to it just like the original synth,
so if you are a fan of those type of sounds then this is a must have.
It doesn't look flashy but it's all laid out clearly –
there is two main windows, one that you can open where you can load two keyboards in the same window and load up two different sounds with basic parameters,
and another window with one keyboard where you have the possibility to create your own patches more easily or just have access to more parameters to manipulate the sound you have loaded.
One thing you also can do is to use up to two independent arpeggiators one for each keyboard with separate sounds, so it is not a sequencer but at least it gives you a possibility to create some patterns for song making.
I haven't seen almost any other synthesizer for android having so many possibilities for sound design and to my big frustration FM synthesis is not something I really understand,
but this synth have given me the urge and initiative to learn the art of FM because I want to ride this beast freely towards a modern digital sound-scape!
There is two small niggles,
it would be nice if you had the possibility to switch to a bigger keyboard when needed to have more control over your playing and the volume on some patches are a little bit too low.
Otherwise I don't understand that he doesn't charge for this as it is easily worth paying for.