AFVs are divided up into five classes; light, medium and heavy tanks, SPGs (artillery guns mounted on slow moving tracked bases) and tank destroyers. Each class plays out very differently thanks to each having a general set of strengths and weaknesses, so it's not just a case of thinking that a tank destroyer is the best vehicle to be in a world of tanks.
Light tanks are very lightly armoured and armed, but as a result are highly mobile, so are best used at the start of a match to scout out enemy positions and take out the enemy SPGs before they wipe out your team. Medium tanks are the real workhorses, having the best combination of speed, armour and weaponry. Heavy tanks in contrast are slow lumbering affairs with huge slow-firing guns that are best used to provide a hammer blow once your team’s light and medium tanks have located the enemy.
If you're this close to a Tiger II heavy tank you're probably going to die right... about... now!
The final two classes, SPGs and tank destroyers are much more specialised, so play out very differently from the three types of tank. SPGs are the slowest vehicle class in World of Tanks, but sport huge howitzers or cannons that can hit enemies on the other side of the map. For SPGs to be effective they need work in close cooperation with light tanks, which spot enemies for them to shoot at.
SPG (artillery) players can deal death and destruction from afar
To aid them, SPG players have access to a special top-down view of the map so that they can rain down fire on top of enemy AFVs. However, while a good SPG player can take down enemies well beyond visual range; SPGs are incredibly vulnerable, as they are so slow moving and are barely armoured.
Like SPGs, tank destroyers tend to lurk at the edge or rear of the battlefield as they tend not to be too heavily armoured and don’t have turrets, so cannot respond quickly to enemies unless they are directly in front of them.
Beware tank destroyers and their great big guns of doom!
In compensation, tank destroyers mount the largest calibre, most accurate direct-fire cannons in the game and receive a special camouflage bonus when in cover behind foliage. Tank destroyers therefore are best used to ambush enemies from afar, often killing or crippling enemy tanks with a single well-aimed shot.