Editions earlier than 2E: never played because I wasn't aware of RPGs in general.
2E (1989 - 1999): By far the most played for me. I was in a group that played almost every week without fail for 6 hours, and a few other groups that played less often and less intensely. These are my high school and college years, and represent the most free time I'll ever have. I'm very nostalgic for 2E for this reason, not on the merits of the system itself, which I only liked because I didn't know differently and 3.0 hadn't come out yet. I played this edition for a few months in 2010 as well when a friend who, despite being an avid player of 3E/4E/PF wasn't comfortable DMing those systems.
3.0 (2000 - 2003): "Almost every week" group switched to 3E when it came out. I instantly fell in love with the system for its open multiclassing and expanded character options; the sorcerer in particular because I always hated fire-and-forget vancian casting. 3E still had vancian casting, but at least I could eschew the "fire-and-forget" part.
3.5 (2004): I left "almost every week" group when I was invited to a co-worker's 3.5 game and discovered that it was possible to have a DM that wasn't a control freak (refused to consider miniatures when his combats clearly required them, hovering over you while you take your turn, refusing to allow you to keep your character sheets between sessions). Sadly, this group didn't last that long due to life happening to all of us.
4E: I wasn't gaming at all when this edition came out, but perusing the books in B&N didn't inspire me to go out of my way to find a group. "Avid player of 3E/4E/PF" later described it to me as "a fun little game, but it's not D&D", which squashed any feelings I had that I didn't give it the chance it deserved.
PF (2010 - 2014): I was involved with two non-concurrent groups (first was "avid player of 3E/4E/PF" deciding to run PF; I joined the second as a result of first group fizzling yet again due to life) that played PF for about 6 hours once a month. I "discovered" Dreamscarred's psionics rules at this point. I vowed to never play a non-psionic character again, DM willing.
5E (2014 - present): PF group did a trial of 5E that I declined to participate in because it didn't really appeal to my tastes (the bad: lack of character customization, "bounded accuracy", and Concentration outweighed the good: the spellcasting system looking a lot like 3.5/PF psionics), and I didn't want to spend my precious gaming time (wife isn't all that supportive of this hobby, but that's a topic for a therapist, not a gaming board!) in a system I perceived as inferior to PF. When they told me they were switching over to 5E indefinitely (if not permanently), I joined them; partly out of laziness, but mostly because good groups are hard to find and 5E isn't horrible, merely not ideal. I still game with them, via Skype, despite moving away.