.us .biz EMD vs .com .net .org non EMD?

Which is better? If you can find a .us or .biz EMD and a .com .net .org non EMD - which is better? Which one will you go for? Which one can you rank more easily?

Also, tell me how much different does - (hyphen) make?

.US does have some strength(no idea about .biz). I have seen many hyphened domains ranked #1. Quality site will obviously be great with a hyphened domain.