I think the camera on this phone is pretty good but there are better options. Honestly, my brothers HTC One S (which is considered mid-range in specs) has a better camera. Can I get great shots from my Nexus 4? Yes. You can get great shots with any phone. I've even seen some good ones from the Galaxy Nexus thread and their 5MP camera. But overall, I would still say get the N4. If a camera is your end all be all, then as others said you might just want to get a point and shoot. But if you want a great phone with a good camera, you can't go wrong with the N4 in my opinion. Check the thread for pictures on this site. For every 2 or 3 bad ones, I see a few amazing ones as well. Also, there are plenty of third party camera apps that really bring out the true quality of this camera (as well as really showing off the shutter speed you wanted which rivals the iPhone 5 in my opinion).
So in general if the camera is about 90% of your concern, id say keep the iPhone 5 you have. It takes amazing pics and is a great phone. But the dropoff between the N4 and the IP5 camera is really not that huge. Some of these folks are saying it takes horrible low light/indoor pics....its a PHONE CAMERA. What phone besides the Lumia takes great low light shots? Look at any comparison video..the differences are minuscule.