The difference is similar to that of Ronaldinho and Kaka. I'm using those two to highlight my point, although Ljajic is known as "Little Kaka", and there have been comparisons between Costa and Ronaldinho. I'm always very skeptical about those kind of comparisons, though, so I don't want to take it too seriously, but it does at least provide a real world example.
Football fans often fail to differentiate between players that occupy a similar area of the field, believing that you can simply exchange one player for another and that it makes no difference, but the truth is that no two players are the same, and even though they may have certain attributes that are similar, it often manifests itself in an entirely different way of playing — both for the player, and the team that they are playing for.
I've always felt that a players running style is important. To use the example of Kaka and Ronaldinho, again, while Kaka almost glides across the pitch, which makes him deceptively quick, as well as giving him the ability to travel long distances with the ball, Ronaldinho — at least in his prime — was far more explosive, damaging the opposition in short bursts, in-and-around the penalty area. Of course, what a player can do with a ball at his feet is also of the uppermost importance, and as we are learning to our cost in the UK, it is the players that are allowed to develop naturally — and thereby maintain a distinctive style — that tend to go on to become great players.
