I recently bought the M6 to replace my M9. What I love about the M6 is that it’s lightweight and not bulky. However, the downside is that it doesn’t have an app to control the features. It’s not hard to adjust the settings on the pump motors—I’m just lazy. 
You also have to make sure it’s positioned correctly on your breast so the suction works properly. Can someone tell me how to resume the pump without restarting the stopwatch after pausing?