I lived in John's Creek for about two years with a boyfriend when I was in my thirties. John's Creek is a decent city overall, in my opinion, and I will explain why here. John's Creek does have a few big positives. Overall, the community is very nice and helpful. There is a nice river nearby that provides recreational sports, and crime is quite low. However, other than outdoor recreation, there really is not a lot to do in John's Creek. There are a few local restaurants, but nothing special that I would go out of my way to recommend checking out.
If you are in your twenties or thirties and enjoy nightlife, this is not the place for you. The nightlife and club scene is absolutely non existent and this can get old really fast. However, if you have small kids there are a plethora of parks that you can attend, that are big and have a safe, open feel to them. Shopping in John's Creek is like a typical middle class suburban town, nothing special. There are a couple of local shops there that I do enjoy going in to, but I would say that some of those have probably gone out of business since I lived in John's Creek.
Overall, I would recommend living in John's Creek if you have small kids or love being outdoors. If you do not fit into either of those demographics, I really think there are many more cities out there that offer a lot more. I never had a bad experience while I lived there, but I also never had a great one. I wish it was a little more exciting, especially during the cold winter months when you could not be outside as much.