The IS tank seems to occupy a slightly peculiar position in World of Tanks perceptions. It is a tank almost everyone even just casually serious about the game gets to play at some time or other, on their way to the ever-popular IS-3. It attracts considerably less opprobrium than the M3 Lee or Jagdpanzer IV, but even so it is not well liked. One does not have to dig far to fine a litany of complaints, but those complaints usually lack a certain degree of punch. Indeed I wonder if because so many people play this tank only to get to the IS-3 that this tank is regarding somewhat unfairly. It is generally compared to its more famous successor, and also I think some people approach the grind as something akin to a job: a boring task with a payoff at the end. Perhaps not the most positive frame of mind in which to approach the vehicle.
Myself I have really enjoyed myself in the IS. I have had some absolutely tremendous games – contesting the centre ridgeline in Mines, doing heroics around the building at the top of the hill on Himmelsdorf, and much more. The overall impression I have is of an incredibly versatile vehicle. It may not have the best armour or survivability, and it may not have the absolute best alpha or dpm, and it might not be the fastest or most agile, but it is no slouch in any department.
The first thing to understand about this tank is that, while classed as a heavy tank it follows the design evolution from the KV-1S. That means, compared to the KV-line of tanks which are all about heavy armour, this line sacrifices some armour for mobility. This is not to see it is unarmoured – it is not. Rather it is selectively armoured. The armour is concentrated to the front, a little less on the sides, and much less on the rear. Compare this to the KV-3 which is better armoured all round, and has the large tracks which can absorb a lot of hits. It also has comparatively fewer hitpoints, which can be thought of another consequence of this design choice. Another comparison with the KV-3 is the base weight – at 44.9 tons the stock IS is almost 20 tons lighter than the stock KV-3.
All this means is while the IS can take a certain degree of punishment, and expect to bounce a number of shots, it will suffer if it has to go face-to-face with many other enemies. It has the added mobility – it should be used. Indeed, the IS has the best power ratio of all the Tier VII heavies, which means it can effectively accelerate and decelerate. It also has the second-best track traverse of all the Tier VII heavies. This allows it to ove into position, fire, move back, reload, rinse and repeat. This improved mobility also gives the IS greater tactical flexibility on the battlefield. It makes it considerably easier to redeploy on the battlefield. Never mistake the IS for a medium tank – it is not – but neither is it a lumbering beast, and like a medium its mobility is part of its defence.
In both the KV-1S and IS-3 an easy argument can be made that their respective guns are better than their equivalents on the KV-line (the T-150 and KV-4 respectively). The same cannot be said about the IS, which uses the exact same gun as the KV-3. I am sure this is one reason why it is popularly thought to be less than brilliant, in that it has the same firepower as the alternate line. However, this overlooks the simple fact that the 122m D-25T is pretty decent gun. Its aim time and accuracy are poor yes – but then, Russian heavy tank guns are hardly renowned for their accuracy – but its alpha is great and the pen is very respectable for tier. Yes it will struggle against Tier IX and better armoured Tier VIII targets, but then then is only reasonable, and like the KV-3 the IS has the mobility to better get in flanking shots. For tanks on tier and below it will be deadly, quite capable two-shotting most lower-tier targets.
The accuracy and aim time do mean that this tank is not best served being used as a sniper, but for close-in work – and this is something that the IS does do well. Like a stuck record I return again to the mobility. It really is the defining characteristic I think of this tank when compared to its peers - but it is a subtle difference. I am also fairly sure it really helps having a well trained crew, particular in Repair since this tank is dead if tracked. Given the IS line is so popular I would not be at all surprised that many people play the IS in less experienced crews, and when they are just less experienced themselves. Ultimately I think all these factors help explain why the IS is not as well-loved as I have found it.
My own record in the IS is 88 matches played with a 55.68% win rate. Along the way I have destroyed 106 tanks, and achieved a damage ratio of 1.19 and a destruction ratio of 1.77. I have not quite managed a Top Gun – though I came close several times. I did get the Ace Tanker, plus 4 Snipers, 3 Confederates, and 2 Steel Walls.
I am going to keep the IS in my garage, though I have now already moved its crew onto the IS-3. I am going to need to train up a new crew for it, and I would like it to be fairly decent just to get the most out of this tank.