As you've probably already seen, when you log into AZT, you'll have two servers to choose from.
As you're IDC/Games players, we suggest you use the "AZT EU" server to avoid lag. However, you're free to choose to play on the other one, but there's one thing you need to keep in mind:
All progress done on one server will stay on that server. This means that all your XP, items, mercenaries, battles, research done on the EU server won't be shared on the RU server and vice versa. The only thing that is shared between servers is your amount of gold.
No account transfer from one server to the other will be allowed.