Thanks for the opportunity to beta test your very fine app. I'm very much looking forward to the official release of Meld; tomorrow is the day I begin to look for it in the Apple Apps store. Yay! Wishing the Meld team GREAT sucess and looking forward to watching the app evolve and conquer! 

1. iPad Air
2. 7.1.2
3. 3 layers, middle layer with large mask of subject leaving background unmasked
4. default
5. In order to get the masking precise, it took MANY mask/erase steps and much too long to accomplish with the current very limited masking brush. Perhaps it was the extensive and sequential mask/erase steps that overtaxed something. On my third attempt I did a very minor amount of masking as a test and the app did not freeze on that try.

There are two apps that handle masking in very different ways that I find to be very precise and VERY fast, making short work of the tedious job of masking to get me immediately back to creating:

• Leonardo, which has the following excellent masking tools which I use often: magic wand, linear gradient mask, radial gradient mask, oval and rectangular mask, transparency and hardness sliders for masking brush, invert mask, feather mask, unlimited undo/redo, and quite a few more tools for masking that I don't use as often.
•  PS Touch's excellent Scribble Selection Tool: simply and quickly outline your subject with that brush and the apps's algorithm automatically fills in the rest of the subject and separates it from the background.