To Install, or, Not To Install
To my mildly geeky eyes, the defining difference between portable apps and regular ones is that portable apps are not installed.
I am a Firefox enthusiast, but was getting frustrated by often losing multi open tabs (I use session saver), after my wife would have several FF windows open, then close them in the wrong order. As she was impossible to train, I added Firefox Portable to my desktop HD, gave it its own unique icon, and use it exclusively, while she continues to use the original. I am careful to close my FF Portable after a session so that she can't mess with it. I have also briefed her (with some success) to close my FF and open her own (the original), should I forget.