Is it better for American immigrants or Japanese immigrants?

First of all, you should consider which of these countries accept immigrants, what are the conditions for accepting immigrants, and which countries you can satisfy. Otherwise, no matter how good that country is, you can't immigrate. What's the use?

Among these countries, Canada and the United States are traditional immigrant countries, accepting rich people to invest and immigrate, and their own countries lack professional and technical personnel. Britain accepts investment immigrants, but the threshold is very high. Japan and Iceland are not immigrant countries, so it is difficult to immigrate.

According to your conditions, all five countries can move freely. Then consider and make a choice from the following aspects: 1, language, can you speak English, Japanese or Icelandic? 2. Employment environment, which country is your major suitable for development? 3. Living environment. If you immigrate not to make a living but to enjoy life, which of these five countries is the best living environment for you?