I don't take high rankings in any melee skill for the same reason I wouldn't take one of these;
To use it effectively as a weapon, you have to be very close to someone. That person in this world is likely to have a gun and won't particularly want to let you hit him, preferring to shoot you as you move into melee range instead.
Melee is very strong in SR5.
You can move very far in one single action phase
(which let you move around his cover before you attack)
You get a positive dice pool modifier for running and attacking someone with a melee weapon.
You get a positive dice pool modifier to avoid getting hit while running.
Attacking with a long reach melee weapon give your target a negative dice pool modifier to avoid the attack.
Targets get a negative dice pool modifier when trying to hit a running target.
Targets locked in melee get an additional negative dice pool modifier to use ranged attacks.
(even if he tries to attack someone else)
If target tries to leave melee range you get to attack him again
(in the same action phase and for just 5 initiative score, normally an attack cost cost 10).
As long as your target is <15 meters away or so you will get
harder to hit if you rush him with a melee weapon than if you spend a simple action to take good cover...

This is how i picture the mono-whip:
http://www.youtuberepeater.com/watch?v=CnefL62NS50&s=43&e=44