Language is the biggest one, it all depends on what languages you know, that will determine how much you’ll succeed. Chinese, Spanish, Vietnamese, and so on. If you don’t know a language, Spanish is by far the easiest of the current AES languages to learn. This will be the make or break as to how well you’ll be able to integrate and live in any country.
Also population growth doesn’t really amount to much. Housing, food, living expenses, and so on are determined more by how well the country is doing, and how much you’re needed.
Not only just for AES countries, but if you can provide a niche skill set or service to any country that needs it, they will bend over backwards to accommodate you. Are you a nuclear physicist, industrial engineer, neurosurgeon, supply chain administrator, capitalist with large investment potential, or any other high demand profession? In those cases any country will make sure you’re very VERY comfortable. If you’re a cashier… sadly you’ll most likely be left behind the door.