THat is hard to say. It delivered a huge payload, for its time. It also had enough guns to truly be a flying fortress, but since from most angles you could only shoot at most a couple guns...
It did bring a lot of guys back home after taking a beating, but, you would never have gotten me in that ball...not for a million dollars.
Actually the payload of the B-17 by the time it was being used in numbers in 1943-44 was nothing special; it really was a medium bomber, not a heavy bomber. Contemporary AC like the British Lancaster and Halifax carried a LOT more bombs.
There a variant of the FW-190 which was heavily armoured in the front, and had a single 30mm cannon. It would saunter up behind a B-17, kill the rear ball gunner and then shoot out the engines one by one. Once the B-17's had fighter escort that tactic stopped. I saw some FW gun camera footage on the History Channel (I was already aware of the tactic) and as an American it was really sickening.
The ME-262 played havoc with B-17's when it encountered them, read, for instance, Adolf Galland's "The First and the Last". The U.S.A.A.F had fighters in orbit around fields which were known to have 262's and would jump them if they attempted to take off.
It's hard to say if the 262 could have been produced in sufficient numbers to turn the war around. One thing for sure, Normandy would have been impossible without nearly complete air surpremacy.
Most of Germany's best fighter pilots were killed early in the War and they did not have the time and resources to train more. In encounters with the U.S.A.A.F, many ME-262's were lost because their pilots were generally very raw and poorly trained.
Want a real jolt?
Wait 'till the touring B17 and B24 come to town and go quickly from '17 to '24...
"The box the B17 came in" and a far better bomb carrier (I htink there were more built as well).