The IS-7 is a Soviet heavy tank of tenth tier. This tank has nothing special to highlight. I.e. it has nothing good and nothing bad. His low profile is an exception, because low profile theoretically gives a good chance of ricochets and increases camouflage value. But these two characteristics are implicit and can be changed in new versions releases. Thereby this advantage is doubtful.
However, this tank has all three main characteristics (armor, speed, firepower) on a pretty good level. Thereby IS-7 is quite popular among the players and the fact, that it can be commonly met on the Global Map, speaks for itself. You will never see weak vehicles on the Global Map.

Pros: not bad cannon, armor and speed.
Cons: there are also no remarkable advantages, which would be used to dominate or even just have fun.