1) Dawnbreaker of Smiting
deals more instant damage + more dot damage = overall higher damage
also knocks enemies down for 1.8 seconds

2) Flawless Dawnbreaker
while slotted increase weapon damage by 2 %

now in both cases there will be + 3% to weapon damage due to the passive - Slayer (increases weapon damage by 3% for each FG ability slotted)
in the case of Flawless Dawnbreaker the increase in weapon damage would be 2% + 3% = 5%
and in the case of Dawnbreaker of smiting the increase would be just 3%

Now which one you guys think is better off?
I am personally prone to thinking that Dawnbreaker of Smiting is a better choice, as it provides higher initial/instant damage + dot damage & also knocks down enemies
plus, worth taking into the account that with the release of DB Flawless Dawnbreaker has been nerfed from giving 5% to 2% of weapon damage

I also don't use Uppercut anymore, so that might play a role for arguing in favor for Smiting

Please give any suggestions, if you have of why I should use Flawless Dawnbreaker instead of Dawnbreaker of Smiting

thx