I've been lucky enough to play this game to end multiple campaigns now, and I can say it's an absolutely delightful experience all the way through. It's really been designed with the emotional weight of a long-term campaign in mind. You end up with a potentially heart wrenching and bittersweet collaboration between you, your friends, your characters, and your world.
WEG is also hackable to suit the terms of your game, and encourages you to adjust things to your liking. I played this once for a GM-less game and once for a standard GM'd game, and it flowed well both times. We also sort of hacked it to work for a prequel portion of our main campaign, and it equipped us with so much meaning-laden imagery to carry forward into 'season 2.' The focus on camera directions has also really informed the way I play games now! I feel more comfortable laying out a scene on the spot. Overall I'd say World Ending Game is something everyone who's ever made it to the end of a campaign should play. And, if you can swing it, I highly recommend the print version - it's a gorgeous object to hold in your hands.