Tried out the IS-2 today. Its actually pretty decent considering it can take damage for whatever units you put behind it (think Churchill). The HE ability is quite strong too. It feels stronger than ISU-152's normal HE shell at the cost of vet and some muni. Near pinpoint accuracy which is very nice when fighting team weapons not in green cover like AT guns or MGs.
By the time you get an IS-2 out, you should have an AT gun or two. Fighting Panthers and other big cats is really a non-issue because you will almost never go up against them alone. Soviets are a combined arms army after all.
psa: the is-2 he shell is accurate because the tank has to be stationary and the AoE is huge, but the isu-152 HE hits just as hard, and at longer ranges
regardless i think i have mastered the art of using the is-2 to a good effect, after a few more games. the anti-infantry capability of the tank is good, IF you are stationary when hitting the enemy, although even then do not expect to randomly snipe x4 models with a single shot
the main issue i had when i made the thread is that panthers can drive up in the firing range of an is-2 and facetank a brawl with low risk, even if the is-2 is higher veterancy