Scrapper, definitely.
As brutes have a lower base and lower damage mod, selfdamage buffs do much less for them than for scrappers.
Rough example:
Scrapper starts at 1 (base) + 0.95 (enhancements) = 1.95. Throw in maxed AaO (0.8) and 4 stacks of PS (1.25) and we end up with 1.95 + 2.05 = 4, twice as much damage.
Brute is at 1 (base) + 0.95 (enhancements) + 1.5 (75 Fury) = 3.45. Throw in maxed AaO (0.65) and 4 stacks of PS (1) and we end up with 3.45 + 1.65 = 5.1, not even half of the relative bonus the scrapper got.
In other words, Concentrated Strike on the scrapper would hit in that situation for 222.7 * 4 = 890.8 damage, while on the brute for 148.5 * 5.1 = 757.35 damage.
The taunt aura is another thing that benefits the scrapper more, because unlike brutes, scrappers lack any other form of taunt in their attacks.
SD barely gets near hitting the scrapper HP or resistance cap while using the T9, so there's little survivability loss going from brute to scrapper.
KM/SD is one of these combos that you really, really want to play on a scrapper rather than a brute.
Thanks for the number crunching! I didn't realize that Brutes hit for THAT much less. Welp, I'm off to make a Scrapper!
I've decided to roll a KM/SD, but I'm wondering if it would be better to roll as a Brute or Scrapper. With the nature of AAO and PS, combined with a fury bar + taunt aura, it seems like I could keep a continuous flow of +dmg going from all three as a Brute. I'm aware of the lower damage index of Brutes compared to Scrappers, but I wonder if the taunt aura to keep enemies in melee makes this particular combination work more in favor of Brutes.
Side notes just in case - I'm not particularly biased towards teaming or soloing, I do both regularly. And I've read in other parts of the forums that it MIGHT be a possible option to keep a perma-PS going (with about 10 seconds downtime, but not including the decay which was not measured), this versus the random BU chance from IOs.
It sounds like a good idea to roll as a Brute, in theory. Any experiences with this? Input I haven't thought of?
Thanks in advance!