TBN generally works fine on multi-hit tankbusters. The math is pretty straightforward: TBN is stronger mitigation than a 20% reduction up until the point where the incoming damage is higher than your max HP, at which point mitigation will start to pull ahead.

In the specific case of Uplander Doom (which is sort of unique in comparison to multi-hit tankbusters everywhere else, in that it does more damage but takes a LONG time to finish), TBN would fall behind Rampart, but would likely beat or pull even with Inner Beast, if you assume that every vuln stack takes effect - but TBN would almost certainly reduce the first hit to 0, meaning that you\\'d have one fewer stack by the time it finished. In practice, I think it would have still been competitive had Midas happened with all of the level 70 skills in play.

TBN would fare a little worse on a solo-tanked Holy Scourge, but everybody used invuln skills for that, and you were technically supposed to split the damage anyway.