I've played a few other RPG systems D&D (3.5, 4, & 5th Editions), Pathfinder, Star Wars D20, All 3 Fantasy Flight Games Star Wars RPG books, Hero System, etc. I've been playing with the old edition of Age Past for over a year now; mostly on & off with one-time adventures with my friends. I decided to try my hand at being a GM and picked Age Past: The Incian Sphere as my first attempt at creating my own campaign. I truly fell in love with this system as my time as GM. My campaign ran for a little over a year with the same core 6 players at our local Comic/Game shop. It was one of the most fun times I've ever had playing tabletop; the Age Past system allows for a nearly limitless amount of creativity without being overly complicated. One of the easiest parts for both my players and I was being able to easily solve mechanical problems and come up with creative solutions. In all of the other systems I mentioned we would have to occasionally open up the rule book in the middle of a session to try and solve the whacky and creative antics my players would get into. But the rule system for Age Past leaves enough wiggle room to solve these same problems without having to slow down the table by flipping through the rule book. It has a similar amount of creative freedom as Hero System, but with way less complexity.
This is where the Revised Edition has blown the old edition out of the water. The creator Jeff Mechlinski has done an amazing job at keeping the open ended nature of Age Past but making the rules even simpler. I currently have a new campign starting in a week using the APISR and I couldn't be more excited. For those that have played D&D; imagine the perfect marriage that was 5e. How it took great elements from 3.5e, but streamlined the rules. APISR does this in a similar fashion; all of the freedom for both players and the GM remain intact, but the mechanics are a lot more streamlined and easier to execute.