Who wouldn't not like the US if you spent all your time living in the Bronx in Washington Heights?
For many people life is more stressful in the US due to many things among which are weather, a much more hurried lifestyle, working becomes the main purpose of life, different language than used to, having to follow every rule/law to the tee which for someone used to having greater liberties could feel as being in a cage, everyone appears to be offended by something so you are always walking on eggshells and being politically correct, people are more impersonal and you can spend a day where you are surrounded by people yet lonely (things as simple as saying hi to everyone when walking into a small store is simply not done in the USA), etc.
Due to the difference of lifestyle, certain Dominican traditions have to be modified. For example, in the DR the major meal happens around noon while in the US very often that same meal takes place in the late afternoon or early evening. That in itself is a difference that many don’t like, but due to work and the intensity of work, no one is home at noon so it has to be done later.
For non-white Dominicans and those considered white in the DR but not in the US, there is an extra stressor they might be subjected to in the US that they hardly if ever went through in the DR. Things such as a harder racism and in certain areas racial profiling can be a shock for someone that never lived through that.
There is much truth to the saying “Americans live to work, Europeans work to live.” Simply change Europeans with Dominicans.