So, with a normal speed weapon with booster (making it 4 attack speed), it'd go like this:
-Brandish: 460% per 750 ms, or 535% per second
-Brandish + Final Attack: 710% per 1170 ms, or 606.8% per second
-Final Attack activating 60% of the time: (.4*535)+(.6*606.8) = 578.1% per second on average
conclusion: if Final Attack takes off the same amount of miliseconds from Brandish as it does Power Strike and Slash Blast, then you'll do an additional 8% more damage over time with a normal speed weapon and booster.
You should note that it's really only useful for bossing. Brandish on 2 or 3 monsters will easily be harmed by Final Attack. 21 Final Attack will probably harm your DPS with Brandish no matter what.
Edit: I just watched the video on the first page and am completely blow away. It seems like FA activates after the first swing of Brandish, resulting in it hitting at nearly the same time as the second hit of Brandish, and therefore causing (almost?) no lag. I'd really recommend that 12 booster, 19 rage, max FA build now.
-Brandish: 460% per 750 ms, or 535% per second
-Brandish + Final Attack: 710% per 1170 ms, or 606.8% per second
-Final Attack activating 60% of the time: (.4*535)+(.6*606.8) = 578.1% per second on average
conclusion: if Final Attack takes off the same amount of miliseconds from Brandish as it does Power Strike and Slash Blast, then you'll do an additional 8% more damage over time with a normal speed weapon and booster.
You should note that it's really only useful for bossing. Brandish on 2 or 3 monsters will easily be harmed by Final Attack. 21 Final Attack will probably harm your DPS with Brandish no matter what.
Edit: I just watched the video on the first page and am completely blow away. It seems like FA activates after the first swing of Brandish, resulting in it hitting at nearly the same time as the second hit of Brandish, and therefore causing (almost?) no lag. I'd really recommend that 12 booster, 19 rage, max FA build now.