I guess that I found it somewhere in its third edition. At some point, I think I picked up some supplements from second. I really liked the change to fourth.
When fifth edition came out, I read it, and didn't find the changes significant enough to convert, or to justify carrying around the extra 300 pages.
The game was always good if you already had ideas and wanted to implement them, but most of the fifth edition material that I've read was dry and uninspiring. I've also always been disappointed with the lack of guidance for actually running a session, setting the scene, creating a mood, etc.
The game has always been more concerned with the mechanics of a situation than any sort of dramatic reason for having the scene in the first place. When I was fourteen, I didn't care, but as I've aged, I've found that the game is a little more fiddly than I want to deal with (or at least in areas where I don't want the fiddly), and I've mostly switched over to M&M (aka HERO lite).
For the sake of nostalgia, I'm sure that I'll browse the book, but I'm not as excited as I was about previous new editions. While I'm sure that it would appeal to my fourteen-year-old self, I doubt that the changes will be extensive enough that it will perform in a way that is appealing to me now.