Is Adobe Flash stable enough compared to native applications?

I agree, it's pretty stable.

The only thing you have to watch out for is memory overruns, which can cause an app to quit unexpectedly.

This can happen in GPU as well as CPU mode, but is more likely to happen in GPU mode.

One issue, I believe, is that the GPU memory can fill up faster than the garbage collector can get to it.  So the app can run out of memory, even if there is a significant garbage collection debt, which if it had run, would have prevented the crash.

One tip is to always dispose your bitmapDatas manually (via BitmapData.dispose() ) when you are done with them, rather than wait for the Bitmaps to be garbage collected.  Manually calling System.gc() is another option, but it can cause a hichkup in your fps.  Note: actually, you need to call System.gc() twice in a row: first pass marks orphaned objects, second pass removes them from memory.

Scrolling big chunks of text/bitmaps is one of the most demanding things you can do, and is one use-case in which you can run into memory overrun issues pretty quickly, from my exp.

Note: for iOS, the iPad1 is the most likely device to have such problems due to the small GPU memory (256mb) compared to large display resolution (1024x768).  If your app runs well on an iPad1, you won't have any issues on the other devices.  Also, try StageQuality.LOW, it can make a big difference as far as performance.