I travelled to Vietnam twice during the last ten years while I was working in China. Vietnam is certainly poorer than China, not to mention the US, but it is developing fast. The most disappointing thing to me about Vietnam compared to China is its much poorer public infrastructure. Every city in China is connected by fast trains, but Vietnam has none. Train travel is slow there. Nearly every Chinese city has a subway system. As of the time I was in Hanoi and Ho Chi Minh City, they had none. Vietnamese cities are extremely dense with noisy and polluting gasoline-powered motorbikes and motorcycles. Nearly all those in China are electric. As I walked around Saigon (one part of Ho Chi Minh City), I was often next to roads congested with hundreds of motorbikes. The noise and air pollution were exhausting.
On the other hand, Vietnamese food, both local and foreign, is typically better than in China. I found even average restaurants were excellent. There were foreign restaurants, such as French ones, that would beat even the best foreign food in China. Perhaps Vietnam’s long and sad experience with colonialism did leave a positive legacy on the variety and quality of the food, at least.
Vietnamese weather is usually lovely, outside the rainy season. The beaches are better than most in China, comparable to the best in the Philippines and Thailand. There is much lovely mountain scenery too.
There does not seem to be much abject poverty in Vietnam anymore, probably less than in the Philippines, even if the average income is not as high. People are generally well dressed, with cell phones and personal transportation, if only a motorbike most of the time. There are lots of personal cars too, but I think fewer per capita than in China. Motorbikes rule the streets.