I dunno, can we see missiles in Northern China given by American for "self defense" ? Though I wouldn't say the outcome is necessarily better, the KMT was comparatively unpopular and quite corrupt .
The early entry of China into the world market would probably see a crowding out effect on Taiwan, Korea, and maybe Japan but they have a head start. Hyundai , Kia, Samsung, Taiwan Semiconductor Manufacture limited would all be one of many competitors instead of the dominating market giants they are today. A side effect of all of this is the lack of another lowest common denominator manufacture after the far East becomes developed, expect inflation to rise sharply 10-20 years earlier than OTL (say 2020-2030) as the far East shifts from export orientated economies.
Culturally there wouldn't be the decades of propaganda and the cultural revolution to bleach out the countless local cultures. While China won't be exporting it's culture like Hollywood a Chinese equivalent of Bollywood is quite likely, goodbye bland generic historical dramas/propaganda that makes up 1/3 of Chinese media. Also without the isolation and bleaching Chinese attitudes towards foreigners would be comparatively better (not too sure on the Japanese though).
Being an ally of the "West" would also mean that the Tibetan issue is played down in favor of the overall struggle against communism. The Korean war (if it occurs) would be a victory for the West with an unified Korea. The Vietnam war would certainly have been won considering the lack of Chinese support, manpower, or safe heaven. Now North Vietnam would still exist short of a Chinese invasion but the corrupt and racist South Vietnamese regime would certainly persist. There wouldn't be as much of the unease surrounding the "rising dragon", especially if China is seen as an ally to the West.
Of course no KMT exile = no Taiwan= massive amounts of resources not going towards armaments, it would also give China less incentive to accelerate the development of their navy.