How is dooming people to Africa-tier poverty not bad? Anyway:
From 1975 to 1995, 900,000 Vietnamese refugees fled to America, mostly in the first few years. This represents approximately five percent of South Vietnam's total population (estimated at 19 million in 1975), fleeing Communist rule. Add up the number of refugees to other Western countries, roughly 500,000 and that means seven percent successfully fled to a Western nation after the fall of South Vietnam. Adding China to the total (mostly for Hoa refugees) jacks the figure up to 1.64 million refugees.
This does not include the hundreds of thousands who died in their attempts to flee (possibly more than 700,000, and at least 300,000 per the United Nations High Commissioner for Refugees's study on the boat people; Rummel estimates 500,000). Nor does it include those who fled to Thailand, Indonesia, Philippines etc or were sweltering in refugee camps in those countries before being turned back. Nor does it include the 200,000 who were killed immediately after the war. Nor does it include the million who were sent to reeducation camps/labor camps in the aftermath of the war. 50,000 of them died too, by the way.
Then we have the defeat of the South Vietnamese being immediately followed by the displacement of millions and persecution of minorities in Laos, Cambodia, and Vietnam. Montagnards, Hmong, Tay, ethnic Chinese and Cambodians, Vietnamese of mixed birth or other non-ethnic minorities such as Buddhist monks, Catholics, Hoa Hao Buddhist sect, etc. all got screwed pretty hard in the aftermath. Mass ethnic cleansing bordering on genocide. China even invaded over Vietnam's treatment of its Chinese minorities.
Then there are crimes during the war itself. Some 500,000 to 600,000 South Vietnamese civilians died during the war. According to Rummel, between 131,000 and 304,000 of these were victims of democide on part of the NVA or VC. The Hue massacre is a famous example.
Overall, Soviet-tier.