The B-29 was not designed to fly a tactical mission - it was a very heavy strategic bomber. It was the most advanced 4 engine heavy bomber platform that saw action in WW2 and was almost a generation a head of both the B-17 or Lancaster. No other ETO bomber of either side was capable of flying the mission the B-29 accomplished with its bombload.
I think weare repeating ourselves. The AR234 was not designed for strategic bombing, a the B24 wasn't designed for tactical support. Both were the best in their classes, so voting for both of them is basically right. If the requirement are as you described, the thread should have been "Best strategic bomber".