The Katyusha Rocket artillery was, as far as I know, way ahead of anything the Germans or western allies had at that time.
The German rockets were superior by far, however as typically the case, the soviets had a LOT more of them and thus had a greater effect on the war than the German Nebelwerfer ever hoped to.
An often repeated report by a the crew of a German 37mm anti-tank gun in June 1941 states that they hit 23 times a single T-34 managing only to jam its turret. From this story, two facts can be learnt: first that by 1941 the T-34 was far better armoured than anything the Germans had even encountered (or even imagined) before, and second: how in hell the crew of the T-34 allowed a single, towed (and thus immobile) anti-tank gun to shoot at them with impunity 23 times? :wacko: That says much about the quality of Germans vs Soviet manpower during those initial stages of the war.
You are refering to the PaK 36 37mm anti tank gun. It was criminal of the German Army to still be using a gun that was obsolete by 1939, let alone in 1941. The only Soviet Tanks they could hope to kill was the BT-5 and BT-7 light tanks.