In contrast, the Bf 109 was a superb dogfighter and above was in its element. JG 1 operated the Bf 109 and Fw 190. The Bf 109 and Fw 190 were used to complement each other in the coming battles over Germany. The Fw 190s armament, considered effective against all enemies, was used against bombers more frequently, while the high-flying Bf 109s engaged escorting fighters. The Bf 109 G-4 was "up-gunned" as well to the Bf 109 G-6, with two MG 131 machine guns replacing the MG 17, and supplementing the MG 151/20 cannon in the nose. The MW 50 (water-methanol) additive increased lower altitude performance but the increase in weight reduced manoeuvrability. German pilots were critical of the Bf 109s fragility, but praised the Fw 190s strong construction; the latter type remained the preference among western theatre pilots.