How effective was the Luftwaffe in strategic bombing compared to the Allies?

At its height the Luftwaffe had a force of around 1,400 bombers for the Blitz against the United Kingdom. According to Richard Overy's The Bombing War: Europe, 1939-1945 between August 1940 and June 1941 they mounted 171 major raids, dropping 28,736 tonnes of high explosives and 3,116 tonnes of incendiary bombs. After 1941 its strategic capabilities declined. Long-range independent bombing had never been a priority, development of the the four-engine Heinkel He 177 started before the war but its development was long and troubled and only entered service in limited numbers. Later operations were of limited scale, conducted with a hotch-potch of types; Operation Steinbock started in January 1944 with around 500 bombers but the force was down to 107 by the end of May.

By comparison the Allies started out with almost negligible resources. The RAF's Bomber Command had 260 serviceable bombers in April 1940 but dramatically increased in size and capability over the course of the war, dwarfing German efforts, with the USAAF joining the Combined Bomber Offensive from 1942. As an example, at the height of their strength, during March 1945 Bomber Command dropped around 75,000 short tons of bombs, more than twice the total dropped by the Luftwaffe over the entire Blitz; the US 8th Air Force dropped a further 74,000 short tons.