Smart scoping with the Needler is not as effective as it might seem; while it does increase the range at which the needles track their target, their flight speed remains unchanged. If engaging a target who is aware of you, fire from the hip for best results.
If you end up on the wrong end of a Needler, a quick thrust around a piece of cover can save your life. Follow up with a grenade to deter the Needler user from following you for a clean getaway.
Warzone and Arena feature two additional variants of the Needler, each being situational but efficient upgrades:
Hailstorm: basically a straight upgrade to the standard Needler with a 50% larger magazine, faster needles, and slightly stronger tracking.