Truth be told I've had no problems with the ISU-152, though sadly my skirmishes seem to crash most of the time before I can even field the darn thing (the game occasionally experiences little hitches of lag at an increasing rate right up till I CTD with a relic report window, which makes me think there's a memory leak somewhere. I sincerely hope the next patch will bring this mod up to a mostly crash free state).
While it is incredibly slow turning and thus has a very difficult time tracking tanks at even medium ranges, its gun has a respectable amount of traverse and it can back up at a decent rate. If I find myself getting rushed by the likes of a Panzer IV or Panther, I usually crank it into reverse while calling units in to support. It can usually kill the enemy tank as it attempts to follow and zigzags in and out of your field of fire. When using the ISU-152, always be conscious of how much room you have behind your vehicle to back up and how quickly you can bring in units to save it if the enemy tries to bumrush it.
