Difficult to say yet, The Hits playlist is rather short, and the Huge logo lets it down.
TMF is good but I was hoping for some actual programmes as well as just Music Videos from this. It does cover a more diverse range of music, but only if you tune in at the right times.
However I've watched more of The Hits than TMF so far.
If you actually want to sit down and watch it, then TMF wins hands down - if only because The Hits suffers terribly from all those logos, red buttons, and scrolling phone ringtone numbers (or whatever they are) that are there just to distract you away from video that's showing!
If you only want it on background music, then one of the radio stations would probably be better than either of them.