Sample Lab is back on iTunes after a severe bug iPad 3 bug forced its removal. Version 1.6 brings more than just a fix though, as it now sports its own Virtual MIDI port and some new sound design tools for samples. Among these you'll find what it calls "automatic MicroAttack", which sounds like it should make sample playback smoother.
• Per-beat attack, queue point & loop control.
• Automatic µAttack makes your existing compositions sound better.
• MIDI CC fix & explicit Sample Lab Virtual MIDI port.
• Fixes for the new (3rd gen) iPad.
• Tells iOS explicitly not to backup samples to iCloud.
This demo video was for the previous version, but it is worth it just to watch BassLine's BPM go berserk.