WaveMachine Labs came with limited (or light) edition of Auria. It looks nice for 25$. For me the only feature I would miss is track freezing beacuse I like to use a lot of these nice plugins at once 🙂 Oh, and Convolution Reverb of course, it is pretty nice. And 8 subgroups :)) Anyway, you always can upgrade to full version option for additional 25$ via in-app purchase.
See also: Best iPad DAWs 2013 overview