Even though I am English, I am not going to persuade you to choose my version of the language. You have to give your personal opinion!
You could look at these issues:
a) pronunciation and accent - which one sounds clearer and more appealing to you?
b) variations in spelling - which are easier for you to remember and use?
c) do you prefer informal or formal English? The former is associated more with US English.
d) can you identify words, idioms and expressions that are differ between the two forms of the language? Which ones do you like more?
e) entertainment and literature - do you prefer more material that comes from the US or the UK?
It may be worth briefly mentioning that there are many other countries for whom English is the native language - Ireland, Canada, South African, NZ, Aus etc and they have variations too. Also there are variations within UK, US and other countries.