I've got P5, P6 and P7 installed on my system, all working in some kind of freakish harmony, lol.  If I didn't wipe off P4 about a year ago... well, that is just too much system resources.  I don't know why I'm hanging on, but i held onto P4 for something like three years after getting P5.

(Yeah, I know you weren't asking me, I just wanted to feel a part of the conversation...)