Every team should be quite happy with these 4 DM's in the world.
McCarthy: enormous pace, good ball keeping, positioning and fine tackles. Weakness: he's not really good at closing up and defending as a fullback/CB
Barry: good passing and vision in the field, good cover as CB Weakness: his pace is gone, slow at times
Gibson: what I saw from him in little time he's a good passer, don't know anything about his tackling ability and also don't know what are his weaknesses
Besic: good passing, good positioning, extreme tackles Weakness: headers and sometimes overthinking of the game
In the next few weeks RM will be in big trouble because of the suspensions / incoming suspensions for Barry and Besic. I think those two learned now how to play together, it's not an issue anymore. Although Besic still needs to clarify his play, as I checked the stats he's the 11th of 290 players in EPL in terms of succesful dribbles in defence... That's on one hand a good thing (he's got the ability to do that) but on the other hand if he fails there will be consequences.
And also I thought that Besic and McCarthy are very similar before I saw them play together. Now I think they're quite the opposite. It was the Chelsea match when I saw them play individually 45-45 minutes I realized that their play is very different it's just the pace which is the same.