What are you looking to spend? Reason I ask is that until android OS starts behaving like iOS where there are core midi and audio functions, any android device is still going to get it's behind kicked for true musical usefulness when compared to Apple iOS devices. The fact that they built low latency audio into the heart of the OS, is one reason all the cool music apps live on Apple iOS, but nearly nothing exists for Android - at least from an 'instrument' standpoint. Garageband for 5$ on iOS is truly an amazing product - even if you couldn't record on it, the keyboards are worth the 5$ alone.

My decision has been made - next tablet device I buy will be an iPad; even older ones work fine for music apps.