Who would have thought that a lightweight supers RPG would a) be good and b) come from the guy behind Mutants and Masterminds?! There's an amazing balance of just enough substance to sketch out a character yet light enough mechanics to keep it fast and easy. It's a great game, especially with kids. I've written about it a lot over the last 5 years so here's a link to my posts. I thought for decades that a "decent" superhero game just inherently needed 300 pages of rules and this is the game that proved me wrong - to myself.
I ran 3rd edition D&D with only short breaks for almost ten years. By the end I was burned out and tired of the system and never expected to run it for any length of time again. I spent roughly 3 years running 4th edition and then took a look at Pathfinder and felt the spark once again. A lot of it has to do with Paizo and the great job they do managing the whole thing. Their willingness to experiment with things is a lot of fun too from Iron Gods to Mythic to Unchained. Some has to do with the community of players and people who post up session summaries, reviews, and aids for the busy GM. A lot of it has to do with the solidity of a system that's been out in the public in some form for 15 years now. I don't know the exact ratios - all I know is that I am having fun running D&D type games again and have been for the last couple of years. Link to ridiculous number of posts about it here.