Sorry to hear that, as I've seen mostly positive feedback about the sound of iRig Acoustic Stage as about 1000000x better than any built-in piezo system (and I agree, with our without bias from working here
).
AmpliTube Acoustic is only available on iOS. With iRig Acoustic Stage you can run direct as it is the audio interface and is akin to miking your acoustic guitar but without the hassle as it clips on and is positioned well already.