No hard feelings involved, Jager. Just stated that your comment as the IS2 would be a good town killer is plainly nonsense.
Also the tiger has a 100mm vertical frontal plate, the panther has a 80mm sloped, yet the IS2 has 100mm sloped or 120mm but less sloped, also 90mm (!) of side armor, how it comes its between the two german tanks?
True, the fire rate is slow and the ammo load is small, still, dont rush or spawn camp with it and it will peform well. Possibbly better than the later Panzer3's, what seemed to be inpotent to the t34/76s...
A 122mm HE shell holds about twice as much explosive charge as the shermans 75mm HE shell, IIRC. 28 of those, probably knocking down 2-3 buildings per shell isn't insignificant. And its stronger armor would allow it to largely ignore the auto ack fire from town and bases (although the 88mm and 17lber man guns would pose a rather large threat if ignored), which means more than any other tank, its able to opperate independent of air support.
As for the armor, it would depend on the variant, like I said. That 120mm section had very little slope, with the effective thickness being about 130mm, and the 60mm glacis plate actually had a greater LOS thickness. Lower hull is going to be about 110mm of protection, or still vulnerable to the KwK 40 and M1 76mm out to about 1400-1600yds, the KwK 36 out to a hair over 2000yds, and both the KwK 42 and 17lber out to over 2500yds.
Up close, its whoever shoots first wins, usually. That means the low ROF puts the IS-2 at a disadvantage.
At medium range, its generally who has the best shooting, provided penetration is still sufficient to penetrate. Since the Tiger I can penetrate the hull out to 2000m (turet out to about 3000m, I would estimate), that means that the IS-2's slower ROF, inferior optics, and poorer balistics are going to hurt it.
At long range, its whoever aquires the range first and has sufficient penetration. This means that the Tiger I is going to have an advantage in the actual gunnery, while the IS-2 will have an advantage in penetration. So skill being equal, it really comes down to how the damage is modeled (is it overall HP based, or is it component/crew based).
Considering that the majority of engagments tend to take place within 1600yds, and only a small fraction of engagments take place at ranges exceediing 2000yds, this means that the IS-2 is going to be sup-par in
most engagments, while being probably about 1/4th of the way up the scale between the Tiger I and Tiger II in those rare long-range engagments.