I personally thought that quarrel running shot and stone shot would be optimal in pvp but after reading some feedback from a krToS player…he was saying for pvp archer c3 is better and for pve quarrel c3 is better. What makes archer c3 better? Thanks 
Q3 archer is a one trick pony and will probably get destroyed by Q3 Catas anyway.
If you go kneelshot+run shot, you are a sitting duck and will get stunned right away, or you will just get blocked.
After running shot/rapid fire goes on CD your kinda useless.
Ranger C3 gives you better tools to deal damage then Q3, overheats and good CDs.
Quarrel c3 is better
I don’t plan on going kneeling shot at all, seems useless. I’d like to go ranger c3 over quarrel c3 to be honest but stone shot stun and running shot seems extremely important in pvp
Picking Running shot without kneel shot is kinda the whole purpose of QS3.
Also makes your ping is below 100ms if you want to run QS3.