Mine is working well, but I know DJI advises to make movements slow and steady, not fast or jerky. Spark 3D sensors take a little time to decipher the signals. Hope that helps. Watch the lights on the Spark and they give you feedback.
I had an issue waving it away, but it was just past sunset. It did eventually work, but I did look pretty dumb waving at it for a good minute straight. I feel that it may just be part of the learning curve and will try again tomorrow.