Which servers work the best and have the less ping in them example USA server,RU server etc?
Ideally the closest one to you physically would be best. It would have lowest ping due to less travel. As far as anything else I think its a matter of how many are on the server; too many could cause slow downs. BUT any region will speed up q times a lot and setting a region could make you wait in q indefinitely or until you finely say well this is just taking too long…
Though I personally find that queue times versus ping is at a happy medium in the EU servers for me. I get about 100 ping average and queue times are usually 0:30-2:00.