Epsxe uses the "esc" key, and it's the most compatible PSX emulator that I've found. I use mamewah with Epsxe and it works great. I don't even have to use a bat file to execute it. Anyway, can't tell you about any other front end's functionality. Mamewah gave me many troubles in the past, but the most recent version was fairly easy to configure, especially with all of the tutorials, and sample configs available out there.
As always, ymmv.