Melee weapons will take two hits to kill most enemies except MAXs. Enemies that are already damaged may go down in one.
Melee weapons do no damage against vehicles, even Flashes, however they can damage Engineer turrets (3 knife swings will put any of the MANA turrets into critical state, but this will not cause it to explode, 4 swings are required). MAX punches are the exception, as they can damage Flashes, as well as base turrets.
One can slash approximately once every 0.8 seconds.
All knife attacks do 500 damage and MAX punch - 750.
Enemies that are unaware or are otherwise occupied will normally be taken out before they can react.
The knife will hit as soon as you press to swing, but beware the delay to stop sprinting if one is doing so.
Hitting non-stationary targets with the knife can be difficult. The zones in which a melee attack will hit differ depending on the distance between you and the target.
At max distance (between half a meter and a meter), one must be looking directly at an enemy to hit.
When right up against an enemy, one can hit within a wide cone - that is, roughly 45 degrees on either side of the crosshair. In most cases, they will be hit (at this range) if they are in the screen.
This angle of uncertainty (i.e. maximum angle between player and target in which the player will still hit) falls off with distance, between the aforementioned values. Put simply, as the opponent gets further away, the margin of error becomes smaller.
The low margin of error at anything other than point blank means the knife can be hard to use properly, since a ready opponent can often move round faster than a player can aim.