Samsung is operating one of its most modern factories in the country, which was a $1 billion investment, and it replied to the initial screen complaints that only 10% of the production goes to Vietnam, the rest is sold all around the world, and complies with the most stringent quality requirements of the company, saying that the whole issue has been blown out of proportion. For all we know, these might be considered normal fluctuations during the quality assurance tests of Super AMOLED Plus displays.
The Galaxy S II aficionados, however, arranged an informal meetup on Sunday, where, among other activities, like giving away purple T-shirts to those who managed to achieve a 5000+ benchmarks score with their phones, they asked the participants to give their Galaxy S II phones for comparison.
They got together 20 units made in Vietnam with 11 imports, and indeed found out some discrepancies in brightness and color accuracy between the local and foreign units. As far as we understood from the translation, in normal use the differences are not that visible, but when displaying plain colors, like blue or pink, the local produce seems duller, despite that all phones compared were cranked up to full brightness.
While all of this might be much ado for nothing, and just cherrypicking outliers, there indeed seem to be wide variations in the screen characteristics as exemplified in the video below, although Samsung says only a fraction of the thousands of units sold in Vietnam have been returned for warranty repair so far. We'll keep an eye on this local riot and report if there are any further developments, be it only for the surprise fact that the phone is treated with such stunts and cult status over there.
source: ICTNews (translated) via Tinhte (translated)