BigOscar said:
Nothing against him, but I can barely see the point in one Dzeko, two just seems excessive. Same goes for De Bruyne and Sneijder, we seem to be being linked with people who we already have players capable of doing their job. You'd think we'd be more in for players we actually need instead
2 key differences:
Mandzukic will work harder for the team consistently. In Simeone's words, "Mandzukic brings character, committment and strength" and Simeone demands 100% or else will kill the player's family :). Dzeko's attitude has improved a lot but he still doesn't throw himself around enough, which can be frustrating.
Mandzukic has scored a goal every 3.18 shots this season compared to Dzeko's goal per 11.3 shots. Last season, it was 4.48 (Mandzukic) vs. 6.48 (Dzeko, in probably his best season ever) and those fine margins can be important. Every year Mandzukic does this, he isn't the most showy striker but is one of the best at actually putting the ball between the sticks and that clinical edge can decide a tense big game when a player has 1 chance to score.
He can also play as a lone striker very well (look at his performance vs. Arsenal a couple of years back) when Aguero gets crocked.