Started 4e when the pdfs leaked before the books were actually out. Loved it all! I Was disgruntled with 'problem players' in my 3.x games; this was a breath of fresh air.
A part of me was put off by the FR books, but I took it in stride ("DDI will fill in the gaps"). I learned a lot while playing in 4E, the game was a solid system. Then the DDI layoffs happened, i was a bit more put off but "




happens". The final straw for me were the Eberron Campaign books. Looking at what was before, and what I had...
Around this time pathfinder was coming out of beta, I grabbed a torrent to catch up on everything... Reading the AP's and the campaign setting... WOW!
Evaluating it all now, 4E taught me so much about running/playing-in an enjoyable game. Keep things rolling, don't get caught up in details, be agile in handling hiccups.
As I was (and still am) going back over the 3.5 rules and understanding the full changes in PFRPG, I began (have begun) to realize that most of my issues with the system were misunderstandings and using to many extra books that my players knew better than I.
In the end I don't regret my 4E games/purchases. The 4e DMG is actually amazing. But many of the lessons learned can be carried into pathfinder (or any RPG). In fact the PFRPG monster creation rules are clearly pulled as a 'why didn't we do this before' reflection of 4e monsters. I'm loving pathfinder now, and I wouldn't be enjoying it so much if 4E hadn't changed me so much.