StuG III Ausf. G

One of the best TDs in the entire game.

Good matchmaking. 

Final gun is powerful enough to penetrate and severely damage all the tanks it may go against in a normal battle.

Extremely good turn rate. Stug can rarely be pinned by medium tanks or even lights.

Very good gun elevation/depression (unlike the SU-100Y, which has beyond terrible depression)

Fairly fast with top engine/suspension.

Very wide gun angle, which is good.

Good money-maker.

If the Stug takes the first shot, it can take a JgPzIV 1vs1.

Top plate of the sloped armor has an excellent angle, so hiding in artillery craters (like the ones at Himmelsdorf) is a good idea.
Take care though, lower front plate is very vulnerable.

Stug III is a very real tank, mass produced, with a lot of history, unlike those bull**it french tanks, which are JUST prototypes and most have never even seen production.
During WWII Stug has been a huge pain in the *ss for the Allies.

Advice: Stugs will very frequently fight KV-1S, which can take them with ONE shot (since his turret and gun are those of an IS-1), so beware!