spark says in his guide that gosac with high item lvl/highe haste is good with (trinket). and serv with lower item. but looking at icyveins guide they say sacrifice is always the better choice at singeltarget with trinket.?
Icy Veins isn't exactly the best resource. You should get your information from reading and analyzing forum posts, not from a single guide. Collective knowledge!
Personally I only run Sac on Council, and nowhere else. I'm not sure about what kind of gear/stats you would need to want to use it on other fights, too, and I haven't really seen any data to that end either.
I use Demo/Sac on Council, Megaera, Twins, and Dark Animus. I use a pet on Durumu, Iron Qon, and Lei Shen. The other fights, I do as Affliction.
Sac/Sup/Serv sim at 207k/211.3k/212.8k for me, single-target. So pure singletarget, even with a 540 ilvl, Sac's not better (at simulationcraft, anyways). If there are more things to Doom, Sac will pull ahead, and if there's burst AoE to be done, Felstorms are good.