tier 1: i've tried all three and i don't really use any except for dominate mind just to do goofy shit. void tendrils would be really awesome for like cho'gall or heroic madness.
tier 2: i really like body and soul. i've always liked body and soul. i am super excite to have it while in shadow. i'll probably stick with it for most fights unless phantasm proves to be needed.
tier 3: if you have the legendary staff, Mindbender (while the initial free cast of MS you get from FDCL doesn't remove dots, the staff proc version of it will. and that just sucks) is the clear choice here. If not, you gotta choose between Mindbender and from Darkness Comes Light. FDCL makes your rotation a LOT more reactive- looking for procs to use MS on (and if you're using DI in the 5th tier that's even more procs to watch for.) Mindbender is a lot more, like, wait for the short cooldown and use it regularly. It's closer to the previous SPriest rotation. People seem to be shitting themselves over shadow word: insanity but as far as PvE it's the weakest of the three and i just plain don't care for it.
tier 4: i chose spectral guise because i can stealth for like 4 seconds now hahahaha oh wow
tier 5: ok i was REALLY excited to hear i could finally get power infusion as shadow. like back in wrath i tried some goofy ass shadow/disc spec just to try to get power infusion but it was fucking awful and i respecced immediately and denied i ever tried it. so i guess it's funny that i don't use power infusion. Twist of Faith is probably gonna result in the highest DPS overall, but I really haven't had a chance to try it because shit's been dying so fast that I'm barely in execute phase. I've personally been rolling with Divine Insight because more mind blasts = more devouring plague. also i've just been doing a lot of five man heroics and those are like all multi-dotting, so there's a lot of SW:Ps floating around proccing insta cast MBs. god i wish raid days would just HURRY THE FUQ UP SO I CAN TRY THIS SHIT ON A BIG KID BOSS
tier 6: lol can't use this shit yet. tbh i haven't even looked at em. it's all like shiny floaty stars right???
there's this post here with lots of pretty shiny graphs that shows simcrafted results of different combos of tier 3 and tier 5 talents on different styles of boss fights. so really i think blizz kind of got what they wanted to achive-- different talents work best on different fights, and you can easily switch that shit up on the fly, like even between trash and a boss.
wow ok before, you'd wait for a shadow orb to cast your first mind blast. now i open with mind blast (ok ok FADE then mind blast. most tanks can't handle that shit.) so that i get as many orbs as humanly possible. well that's assuming i'm not starting a fight with 3 shadow orbs. if i am, i would use DP first then MB and HOLY GOD you better be ready to fade when you open with that. DP is a beast now.
mindbender, next. sw:p next, so that i can start ticks and try to get EVEN MOAR MINDBLASTU. then vt, and fill with mind flay like always. and DP when you have three orbs. Execute phase is 20% now, down from 25%, and on trash mobs i barely have time to get a second sw:d off because the first usually kills it.
i like it! the changes to shadow orbs are pretty great, and it makes your overall damage a LOT less RNG based.
also ok mastery is a chance to proc extra ticks dots. i have a staff that procs extra ticks of dots or of mb or anything. can they just proc back and forth between each other?? god that would be SILLY.