Another "Which tier8 premium" topic

Falathi: I`d say - keep the gold for now. You can basically buy these tanks easily anyway, so let me ask you a bit different question: what is the key point you consider when thinking about buying a premium tank? What is most important? 

Is it the earnings? Credit making? Reliable playing style, relative ease of play? Perhaps more difficult, but possibly more rewarding/interesting playing style? Crew training? 

If I knew answer to these questions I`d be able to offer a better, more elaborate advice