I do on the computer, but not on iOS. I prefer to play them on the real thing though, the controls are never quite right in emulation.
I mostly use Stella for development, the integrated debugger is most excellent. You can see it in the screenshot at the bottom of this page:
http://stella.source...t/screenshots.php
The grid in the upper-right with 80, 90 ... F0 for the Y labels displays the entirety of the Atari's RAM