Moroccan centre-back Mehdi Benatia has had a great rise to prominence this last season; his stunning performances for Roma helped them qualify for the Champions League and finish second in the Serie A.
The 27-year-old only joined Giallorossi last July in a €13.5 million deal from Udinese, but has quickly established himself as one of the best defenders in the Serie A.
Mangala on the other is four years Benatia's junior at 23-years-old; he's a France international and currently practises his trade in the Primeira Liga for Porto. He joined them in 2011 from Standard Liege in a deal worth €7.5 million.
He has been a commanding figure in the Porto back line since his breakthrough in the 2012/13 season. His ability and potential has attracted many admiring clubs across Europe.
First of all both target are absolute giants at the back. They both stand at exactly 6ft 2in tall, and both have enough muscle to deal with the rigours of the Premier League, that is for sure.
Age could be an important factor in determining who would be the better signing for City. Benatia at 27 has four years more experience playing at the top level than Mangala does.
However Man City aren't in desperate need of an experienced defender, skipper Vincent Kompany, 28, Martin Demichelis, 33 and Pablo Zabaleta, 29, are all the experienced defenders that City need. So Man City could look to Mangala for his potential and longevity over Benatia.
Neither have Premier League experience so they would both need to adjust and adapt which can sometimes be difficult; City have no other Moroccans in the squad whereas they do posses a number of French players.
Last season Mangala featured 33 times for Porto in all competitions picking up 12 yellow cards, 1 red and 5 goals.
Out of the 33 games he played Porto won 17 of them, and their back-line kept clean sheets in 11 of those 33 games. Benatia also appeared in 33 games for Roma, all of which were Serie A matches. He was given 8 yellow cards and also scored 5 goals. Roma won 22 out of the 33 games Benatia played and kept 19 clean sheets.
To put that into perspective, should City sign Benatia he would only offer them a considerably better chance per game of keeping a clean sheet than if they signed Mangala, but the Frenchman posses the same goal threat as Benatia despite being younger.
With the £30 million+ price tags that are on the heads of both players, it seems it would be more sensible for City to put their money on Benatia. Mangala might have potential but he doesn't come from that strong of a league to command such a high price.
He is also behind Liverpool's 24-year-old defender Mamadou Sakho in the France World Cup team, which could also suggest something about his current ability.