Honestly, I recommend any Apple iOS over Android for any audio consideration simply because they have much better audio drivers that allow you to record with low latency.
Audio input just doesn't seem to be a priority for android yet.
Research:
http://gigaom.com/2014/06/26/with-androids-next-l-version-users-finally-get-to-be-t-pain/ It seems that with the upcoming update to Android "L", Google is touting latencies as low as 20ms, but that is still not suitable for multi-track over-dub style recording.
If you just need to record one mono track with no over-dubbing then android will be fine, but I don't see any reason not to go with the better experience and larger support base of Apple for audio.
P.S. For what it's worth; I am a full-time android phone and tablet user. I have tried an iPad 2 in the past and it was just a better experience for my recording & production needs.