I've been playing Ingress for a couple months and enjoy it. I suspect many people on this forum would take swipes at the game since it is Android-only at this point. I acquired an Android device purely to play the game and use my iPhone as a hotspot to bridge the data service to the device.
One of the major goals of the development staff was to get people "off the couch" and out into the outdoors. That's the huge plus of the gameplay. Anyone that plays Ingress will do a lot of walking. You will see other parts of your city you have missed if you travel out to see other portals. And if you only stay in areas where you are familiar you will gain an appreciation of public art and other landmarks people typically submit as portals.
It is much like an MMORPG except instead of moving your avatar in a virtual world, you actually drive, bike, and walk to locations in the real world. Instead of chatting with your teammates over voice-chat, you will be able to meet up with people in your area face-to-face.
The gameplay itself is very simple at this point. There's really only two aspects of the game: acquiring resources and using the resources to take over territory from the other side. There are some subtleties of the game you will have to learn, but once you learn them you can reach max level in as little as a month if you play a lot. It took me two months. Two months of a lot more exercise than I was getting in the past.
The developers have put this whole story together for the players. If you're into that type of fantasy, awesome. I personally don't pay a whole lot of attention to it and rely on other players to let me know how the gameplay changes over time. The developers have listened to the players and improved the game. They also occasionally tweak the game parameters to try and influence player behavior. Probably as experimentation.
I don't play nearly as much anymore. But every once in a while I'll get out, do some more walking, and take back a few more portals. In the process of playing the game I've seen more parts of my community and met lots of people on both sides. I've been very happy with the experience.