After seeing this thread, I am trying out the free trial of MOG, but I have not subscribed. I would have to say the jury is still out. I'm a Spotify subscriber and I've been very happy with Spotify. I've been trying listening to some of the same tracks on Spotify and MOG. I'm using a FiiO E17 DAC/amp through USB on my Windows notebook. So far, I've been unable to hear any difference on most tracks. I don't know how to determine what quality individual tracks are streaming in on Spotify. I understand that some are apparently less than 320, but so far, I really haven't been able to tell any difference in SQ. Perhaps the tracks I've compared happen to be streaming at 320 on Spotify as well, so that's why I can't hear a difference.
I'm still trying MOG to see if I like the features, navigation, available tracks, etc. I have noticed that sometimes songs on MOG are slow to start and then drop out during playback. I have a fast Internet connection, so that shouldn't be the issue. So far, the reliability of playback on Spotify is better than MOG.
As I said, I'm quite happy with Spotify, but I'm just trying MOG based on some of the posts in this thread to make sure I'm not missing anything. I don't use either service with my phone, so I'm only interested in playback on my Windows PC. I will have to keep testing and perhaps I will subscribe to MOG for awhile just to continue my testing. At this point, however, I'm not finding MOG to be any kind of a "home run" over Spotify.