Obviously, you only use them when you are using manyshot or 10kstars. Go ahead and try Shiradi.. 200 less HP, very low to non existant burst DPS. Think about it this way. 4 arrows with a manshot in shiradi will be what.. 2K damage, but with adrenaline, you are looking at 10k damage, and if the mob is pinned and you are using slayer arrow, that's a ridiculous amount of 15-20k x4.
Take a look at my elite shroud video posted yesterday, specifically how I 1 shot elite portals with adrenaline+slayer+10kstar, or even part 2 with the 4 red names kill, or part 4 when I unleash a fury shot on harry.
I did a 3 rounder on elite harry in part 4. I'm not even sure I could do it in 10 rounds with shiradi.
I can keep telling you how FotW is better, but in the end, I think you should try it on your own. Try both EDs on your monkcher.