Hey rocoteh, regarding the Soviet IS-1 and IS-2 tanks. the IS-1 should have more attack power than the Panzer IVh, and the IS-2 should I think be more closer to the Tiger tank. I am not sure but I think IS-1 was designed as an answer to the Panther tanks of Germany and the IS-2 was designed to combat the Tiger. There was also a IS-3 designed to combat the king tiger tanks and was the most powerful tank of World War 2.
Comparisons:
Panzer IVh:
Armament: 75 mm Gun, MG 7.92 mm
Crew: 5
Armor (max.): 50 mm
Speed (max.): 40 km/hr
Dimensions: 5.93 x 2.88 x 2.68 m
Weight: 23.6 ton
Jagdpanther:
Armament: 88 mm antitank gun, MG 7.92 mm
Crew: 5
Armor (max.): 100 mm
Speed (max.): 46 km/hr
Dimensions: 6.86 x 3.28 x 2.51 m
Weight: 45.5 ton
Jagdtiger:
Armament: 128mm Pak 44 L/55 gun
Crew: 6
Armor (max.): ??? mm (more than jagdpanther though)
Speed (max.): 17 km/hr
Dimensions: 7.26 x 3.65 x 2.95 m
Weight: 70.60 ton
Panther:
Armament: 75 mm Gun, 3 x MG 7.92 mm
Crew: 5
Armor (max.): 110 mm
Speed (max.): 46 km/hr
Dimensions: 6.88 x 3.40 x 2.98 m
Weight: 45.5 ton
Tiger:
Armament: 88 mm Gun, MG 7.92 mm
Crew: 5
Armor (max.): 100 mm
Speed (max.): 38 km/hr
Dimensions: 8.45 x 3.40 x 2.95 m
Weight: 56 ton
King Tiger:
Armament: 88 mm Gun, 2 x MG 7.92 mm
Crew: 5
Armor (max.): 180 mm
Speed (max.): 38 km/hr
Dimensions: 7.2 x 3.6 x 3.09 m
Weight: 68 ton
IS-1:
Armament: 85 mm Gun, MG 7.62 mm
Crew: 4
Armor (max.): 160 mm
Speed (max.): 40 km/hr
Dimensions: 8.32 x 3.25 x 2.90 m
Weight: 46.0 ton
IS-2:
Armament: 122 mm Gun
Crew: 4
Armor (max.): 160 mm
Speed (max.): 37 km/hr
Dimensions: 9.9 x 3.09 x 2.73 m
Weight: 46.0 ton
IS-3:
Armament: 122 mm Gun
Crew: 4
Armor (max.): 200 mm
Speed (max.): 40 km/hr
Dimensions: 6.67 x 3.20 x 3.43 m
Weight: 45.8 ton
although the pather seems to have more armour than the tiger, i think the germans used better quality steel for the tiger tanks. this is the link i used:
http://www.military.cz/panzer/index_en.htm