Duration : vs duration is more by 6 seconds than the fb
It Works after death : vs users are able to kill you even after they die cause the skill keeps doing damage after you die
Strength : vs is way stronger than fb as I already mentioned a max fb will do a damage around 40-41k but in the other hand we have vs that does at least 65k when maxed

So according to this I suggest that you buff that skill where we can at least do around 48k damage at a max level , I know many vs users will oppose this but you really have to do something about the fb skill since you can't nerf the vs , fb should become stronger than it is because honestly we don't feel it was worthy to max fb since there's only 4-5k damage difference between level 12 and 13 and you have no chance when 1v1 with vs player

Hopefully you take this suggestion into consideration