If you like fast games with simple mechanics allowing to focus on the story, Abstract Dungeon is a game worth reading.
The beauty of the system lies in the fact that any kind of character trait (such as special abilities, magical powers, personality traits, etc.) are easily implemented and used throughout the game session. This means that a Trait such as "I'm a small flying fairy" can have as much narrative power as "My enchanted two-handed broadsword", which can disturb some players used to more tactical games. For creative players, on the other hand, the system offers a wealth of possibilities for building exciting stories centered on their characters - stories that are not just about how many hits it took to slay the monster at the last encounter.
Interestingly, the system is versatile enough to adapt to virtually any other heroic setting with bigger-than-life characters (eg: super-heroes, Star Wars, Indiana Jones, League of Extraordinary Gentlemen, etc.). The only effort would be identifying 4 appropriate abilities - and the ways in which they can be used to overcome obstacles / the ways in which the PC's foes can use these abilities to hurt them. I bet any GM with basic knowledge of the setting should be able to do it in no time. However, this would have deserved a chapter in the book, since it expands tremendously the interest of the system.
Besides, the book is not exemplt of flaws. One of them are the illustrations, sometimes childish, sometimes of poor quality, sometimes both... Fortunately, the text is well written and the layout is pretty clear, so that the PDF reads well even on a small screen. That's the most important, I guess. Also the character sheet could have deserved a little more investment, to be more inspiring/exciting. Again, that's not a big deal, because I like producing my own character sheets, but still... And, finally, I was really disappointed by the 3 adventures proposed in the book, which are all superficial and lack consistency (and stakes too).
All in all, you should really have a look at Abstract Dungeon if you're looking for a system to run easy and fast-paced games, or you want to use your old medfan modules without having to bother with endless lists, tables and complex systems. I believe that many GMs will be able to define the characteristics of obstacles and encounters for Abstract Dungeons on-the-fly, although I'd rather do that beforehand because I prefer focusing on the descriptions and the rythm of the game. You might also be interested in AD if you're looking for a simple system to run epic and fast-paced adventures in your own heroic setting. Finally, AD is also an interesting option if you're running initiation games to new players (especially young ones).