Something was forgeten on the vote. Missing the two 4th generation operational MBT: the K2 Black Panther and the Type-10. With the Leclerc they are the only 4th Gen MBT operational at this date more advanced technologicaly than the leo2 and the Abrams.
My 5 favorites tanks are:
The Type-10 has the advantage to have a very good mobility in urban combat, it has a speed of around 70 km/h on backward and it can turn very quicly like when it firing.
His main problem is his main gun who seems to be a L44
The K2 Black Panther has a better gun. This is a L55 who is very efficiency with the good FCS featured, the K2 has also a good protection and mobility. It has also a good auto-reloading system similar of the Leclerc's one.
I heard that the program took late because of some problems of reliability.
The Leclerc has also a very good electronics and a very good mobility. His Battle Management system is compatible with a french battlefield network system and it has one of the best electronic gyro-stabilisation. And it has also a polyvalant protection with a lot of properties similar of the leo2's protection. The Leclerc has the luck to be oldest 4th generation tank so it had the time to have "post-production" upgrades necessary for usual problems of reliability.
But this is the most expensive tank of the world, with not a good quality/price, France considered it as a money pit.
The M1A2 had greatly improved his electronics and protection. His FCS is very reputate, and his protection in Uranium seems to be very good. Australia (a great ally of USA who bought previous versions of Abrams) wanted to have this kind of armour, USA refused to export it, I think that it's a good one. The M1A2 has also the experience of Iraq with an urban kit the TUSK who inspired british and french on their tanks.
It has the same problem of the Type-10: a small canon L44 and a not exceptional mobility.
The Leopard 2 has the particularity to be excelent in all domains, it is very polyvalant. Great mobility, a great canon with new rounds in titanium very efficiency. A good polyvalant protection.
Maybe his only problems is his age, the leo2 A7+ is maybe one the last version so the tank has may be no future.