It sounds just as good as the PC version did. And the controls work great on an iPad 4 screen, it detects my finger presses accurately enough that moving knobs or pushing buttons is never a problem. Even while I'm holding several keys and move several knobs at once it doesn't flinch.
Plus a few new features, like the Voyager-esque X-Y pad, there's two of those, where you can assign any parameter to the X or Y directions. Wish there was a reverb effect though, not just chorus and delay.
The pads and effects are on separate "screens" so they don't clutter up the main interface.
Attached the headphones to a channel on my 12-channel mixer, and it sounds just as loud and bassy as any other synth I have.
I hope they bring more synths over to this format, they're good sounding and way cheaper than the PC versions, while still looking the same.
Plus it seems more natural to play a touch keyboard and physically touch the dials rather than click and drag with a mouse. I've never been much into MIDI control and even more cables cluttering up the space around my computer.
This one cost $10, the PC version more than $100.
The Moog Modular V will probably be too cluttered on a 10" screen, though.
I also like that you can resize the keyboard.