Tierstack Melee Or Heavy Melee For Assassin?

I have been trying to decide for such a long time, so I decided to ask people here.

I don't take any of the credit for the example builds
Tierstack: (example: https://wynndata.tk/s/ty8mul)
Pros:
Higher raw base dps (not taking vanish into account)
More attack speed = more fun
Courage powder special for a bit more damage
Cons:
(estimate) equal or maybe less dps considering pauses for vanish
Very low sustain, especially ms and ls
slightly glassy

Heavy: (example: https://wynndata.tk/s/4i1tny)
Pros:
Attack speed works well with vanish timing
You one shot things quite a lot
Quake powder special for MUCH more damage
Tanky
Great ms and ls sustain
Cons:
Less attack speed = less fun
Very annoying when you can't one shot things
Lower raw base dps

If I'm not taking something into account, please tell me!

 

Usually heavy is better solely because of how vanish works, as most of the cons of heavy are taken away by vanish

 

Vanish quakes are op and heavy has better synergy with vanish

 

Heavy melee, because one quake can sometimes do more than 150k neutral damage (ofc, using vanish, t6 earth powders, and critical hit), enough to take away half the healthbar of most legendary island bosses