Pretty much gonna be impossible to get a direct answer for many reasons...
This forum is mainly for Aeria AVA (USA and EU servers) and the only way for you to know the ping is if you try it yourself. You can't really guess the ping.
As for the the different versions of AVA... They are all different in their own unique way. All of them have separate servers so if you want to play on a certain server you have to download that direct version of AVA which takes a long time because you have to translate everything.
The best bet is to download AVA on Aeria Games which is the English version. It has servers for both EU and USA so being in Greece you may get around 150-200 ish ping on the EU server. Definitely playable.