I just sold my Phantom 2 and intend to pick up a Spark. I think the image quality of the Spark is excellent for what it is and agree that 95%+ of those shooting video won't notice or care that it is 1080. I shoot footage that is used on TV in the outdoor (i.e. hunting) industry. Everything I shoot is in 1080, as I don't own a single 4K camera of any sort. 1080 works and works well. Heck most of the broadcast stuff across the air is still only 720. Not to take away from the Phantoms or Mavics, but the Spark fits a huge market out there. For myself, while my Phantom with a GoPro took amazing footage and was fun, it was too big, too cumbersome, took too long to set up, and was just over all a pain in my back side. The Spark should fit well in with my gear and my needs. I am usually running short on space when it comes to packing gear into the field and I am always trying to conserve both weight and space. It should also allow me for quick setup shots that are more spontaneous, something much needed in my world of shooting video. Plus, from a personal standpoint, it will be fun to use on family trips or other just general life situations.
I am looking forward to the Spark.