Well, I must confess that I am no expert on the B29. However I note the following text off of Wikipedia...
"The most common cause of maintenance headaches and catastrophic failures was the engine. Though the Wright R-3350 would later become a trustworthy workhorse in large piston-engined aircraft, early models were beset with dangerous reliability problems, many caused by demands that the B-29 be put in operation as soon as possible. It had an impressive power-to-weight ratio, but this came at a heavy cost to durability. Worse, the cowling Boeing designed for the engine was too close (out of a desire for improved aerodynamics), and the early cowl flaps caused problematic flutter and vibration when open in most of the flight envelope. The 18 radial cylinders, compactly arranged in front and rear rows, overheated because of insufficient flow of cooling air, which in turn caused exhaust valves to unseat.
These weaknesses combined to make an engine that would overheat regularly at combat weights, particularly during climbs after takeoff. Unseated valves released fuel-air mixtures during engine combustion that acted as a blowtorch against the valve stems. When these burned through the engines disintegrated and caught fire. A fire that was not immediately contained in the forward part of the engine by fire extinguishers became impossible to put out. An accessory housing manufactured of magnesium alloy in the back of the engine would often catch fire and produce heat so intense it burned through the firewall to the main wing spar in no more than 90 seconds, resulting in catastrophic failure of the wing.
This problem would not be fully cured until the aircraft was re-engined with the more powerful Pratt Whitney R-4360 "Wasp Major" in the B-29D/B-50 program, which arrived too late for World War II....frequent replacement of the uppermost five cylinders (every 25 hours of engine time) and engines (75 hours)..." were required. Hmmm! I'll bet the lanc didn't require that kind of maintenance!
That doesn't sound to me to be a particularly reliable engine at all! The Merlin engine was certainly the most univerally used engine of the war, and although there have been criticisms on this board on the use of coolant, certainly Mosquitos were used in India, and Spits, Lancs and Hurricanes were used in the dessert with no serious engine problems.
The comment earlier on by Thorlifter "weight is weight and it doesn't matter..." Certainly you can pack a lot more incendiaries into a bomb bay than, say 1000 lb bombs just because of the geometry of how that tonnage is packaged.
So, as I see it the Superfort was a fast bomber (score 1 for superfort). Longer range for the superfort (score 1). Maximum bomb tonnage was about equal (draw). Handling charactaristics (score 1 for the lanc, do you really think that one man could do a circuit and bump in a superfort and say that it flew as effortlessly as a biplane?). Reliability (seriously folks! based on the engines alone, you've got to score 1 for the lanc! Only deep American pockets could afford to keep that sucker in the air). Superforts never used in anger in any precision bombing role (score 1 for the lanc). Historical versatility in combat and longevity of service career during WWII (score 1 for the lanc). I've got the lanc ahead on points 4-2. Yes the superfort was a next generation bomber, but serious teething troubles were evident throughout it's service history in WW II because of its rush to service.
Hey! The superfort was the aircraft that ended the war in Japan! Harris would have loved to have had the same success against Germany! But it's a heck of a lot easier to burn a bunch of wooden houses and factories (which is why they were able to use all incendiary loads) than it was to attack the military-industrial complex of fortress Europe. It also helps to have the atomic bomb!
JDC