IS
The greatest Assault Heavy at Tier 7, we have the IS. Considering just how poorly armored practically everything is at Tier 7 and below, the D-25t is a fantastic gun. 175mm of penetration will reliably punch through most enemy armor, and the tank’s gun handling is surprisingly decent. That just leaves the DPM and alpha damage, both of which are phenomenal for the Tier and can easily dispatch anything within moments.
Unfortunately, as previously mentioned, nothing at Tier 7 particularly has anything to mention in the way of armor – including the IS. You might have decent luck with side scraping and weird angles on the turret, but nothing you can rely on too much. The plus side is, unlike many other vehicles, you actually gain mobility for your lack of armor – excellent mobility at that.
The top speed of 34 km/h isn’t the best but is also nothing to scoff at considering the high power to weight ratio. The most important aspect, however, is the outstanding hull traverse speeds that make you more of a Medium Tank… with a ridiculously oversized gun.