Which is the best end game Gem reward for ST ?

I mean reward from this quest, which is the best?
http://pathofexile.gamepedia.com/A_Fixture_of_Fate Merciles

Cast on damage taken without question,

Its one of the most amazing utility gems one can get their hands on (8-10 chaos in Nemesis)

When connected to Enduring Cry + Molten Shell + Enfeeble you will have a flat damage reduction of up to 45 % which is essential for Nemesis at least.

it also has the distinction of being more valuable than the others (multistrike,chain GMP) so if you really wanted one of those get Cast on damage taken trade it with someone for chaos and use said chaos to buy whatever other gem and keep profit (the only other gems remotely useful are Multistrike {if you use double strike} and GMP {for your Spectral Throw})

All new trigger gems. Cast on damage, cast on crit and so on. They are just the most expensive right now.
Becuase other "drop only" 0 qality gems can be bought rather cheap and easily, maybe except multistrike.