FTS,
After WWII, one of Wingate's lieutenants, Michael Calvert, wrote a book (Prisoners of Hope), which described in detail the second (i.e. 1944) Chindit expedition into Burma. In this, he mentioned a captured Japanese document, containing an appreciation of the fighting qualities of their enemies.
In this, the Japanese listed as most effective the Chinese, second most effective the Australians, third most effective were the Americans, followed by the British, then the Gurkhas, and finally at last place the Indians. At least during the earlier phases of the war against Japan, it was Chinese forces who offered the most successful resistance against Japanese invasion.
Wingate arrived in Burma far too late to be able to influence events in 1941 - 42, and the British were bundled out of that colony with almost the same ease as they were defeated in Malaya and Singapore. A major - perhaps the major - achievement of his first (i.e. 1943) Chindit expedition was to demonstrate beyond any doubt that European soldiers could fight in the jungle just as well as anybody else could. (It also disrupted the Japanese plans for Burma for that year).
According to the Japanese themselves, the following year's Chindit expedition into Burma saved India from conquest. When debriefed after the war, the Japanese commander in chief for South East Asia admitted that he had had to commit one entire infantry division, plus a large part of another, just to pursue the Chindit forces who were harassing his rear areas. In his estimation, any one of those formations would have been sufficient to "swing the balance" at the two critical battles (Kohima and Imphal) then being fought at the gateway to India.
Wingate was a controversial character, variously described as "brilliant", "eccentric" and even straight out "mad". To a degree this is understandable - it was a time that called for thinking "outside of the box", and in the process, the army establishment was shown up as wanting.
Calvert's 1952 work Prisoners of Hope is an informative read about those times and events.