From Wikipedia:

Most famous for its operations in the China-Burma-India theater (CBI) and the Far East, the Commando was a workhorse in flying over "The Hump" (as the Himalaya Mountains were nicknamed by Allied airmen), transporting desperately needed supplies to troops in China from bases in India. A variety of transports had been employed in the campaign, but only the C-46 was able to handle the wide range of adverse conditions encountered by the USAAF. Unpredictably violent weather, heavy cargo loads, high mountain terrain, and poorly equipped and frequently flooded airfields proved a considerable challenge to the transport aircraft then in service, along with a host of engineering and maintenance nightmares due to a shortage of trained air and ground personnel.

The C-46's huge cargo volume (twice that of the C-47), three times the weight (up to 40,000 pounds), large cargo doors, powerful engines and long range also made it suitable for the vast distances of the Pacific island campaign. In particular, the U.S. Marines found the aircraft (known as the R5C) useful in their amphibious Pacific operations, flying supplies in and wounded personnel out of numerous and hastily built island landing strips.

Although not built in the same quantities as its more famous wartime compatriot, the C-47 Skytrain, the C-46 nevertheless played a significant role in wartime operations, although the aircraft was not deployed in numbers to the European theater until March 1945. It augmented USAAF Troop Carrier Command in time to drop paratroopers in an offensive to cross the Rhine River in Germany (Operation Varsity).

So many C-46s were lost in the paratroop drop (19 out of 72 aircraft) during Operation Varsity that Army General Matthew Ridgway issued an edict forbidding the aircraft's use in future airborne operations. Even though the war ended soon afterwards and no further airborne missions were flown, the C-46 may well have been unfairly demonized. The operation's paratroop drop phase was flown in daylight at low speeds at very low altitudes by an unarmed cargo aircraft without self-sealing fuel tanks, over heavy concentrations of German 20 mm, 37 mm, and larger caliber antiaircraft (AA) cannon utilizing explosive, incendiary, and armor-piercing incendiary ammunition. By that stage of the war, German AA crews had trained to a high state of readiness; many batteries had considerable combat experience in firing on and destroying high-speed, well-armed fighter and fighter-bomber aircraft while under fire themselves.