American versus British

I'm guessing the American accent is a bit more useful on a global scale, due to the influence of media and US economy, but it certainly depends on the situation.

I agree with Leo. 

In Korea, when we first learn about English, we learn with American accent.

There are some reasons why we learn with American accent.

Economically, we interact with America a lot. When we have contracts or business with them, it is better to speak English with their accent. 

I think this is the biggest reasons why we value American accent. 

As I say one more thing, most hollywood movies such as Marvels have American accents actors and actresses :) If you want to listen to what they're saying, you'd better learn English with American accent!

I honestly think that the vast majority of English learners would be better off learning the American variant. I would only recommend British English to those planning on doing business there or moving to Britain. Obviously there‘s also the occasional language enthusiast who‘s fixed on learning that specific accent and that’s OK, but other than that I think the safest bet is American English. Here are a my reasons:

• The vast majority of English native speakers (67 to 70 per cent) live in the United States (link).
• The United States is undeniably the biggest economy in the world and an unrivaled military superpower so they have a huge influence on international business and politics.
• The vast reach of Hollywood means that all of us are constantly exposed to American English and culture, and chances are that non‑native speakers around the world will be more familiar with that variant as well.
• Even people from other English-speaking countries are exposed to American media on a constant basis, so they will be familiar with it too.

All that means that even though a British accent may make you sound more distinguished if you want to increase your chances of being understood across the globe, American English is the way to go. By the way, I should point out that this does not only apply to pronunciation but to vocabulary as well. Check this video. I think you’ll agree that most people haven’t even heard of some of these British English words.