I am looking up top players in 2s and some players are using 2 one handed weapons and some are using 1 two handed weapon. Is either one efficient and is there a different build for each?
There is a build for each, both work though. 2 handed has Obliterate focus and 1 handed has Frost Strike focus. Play both and see which one you like more.
2h gives you a passive from Might of the Frozen Wastes, which gives a huge buff to Obliterate. This is to make up for the missing enchant you get from Runeforging 2 weapons (with Rune of Razorice & Rune of Fallen Crusader).
Its personal preference, I like 1h because it provides more damage outside of Pillar of Frost. Its more forgiving than relying heavily on your Pillar setup which is easy to counter.
You can use either weapon for the same build. Its still the same playstyle.
Do you want to sacrifice sustained damage outside of Pillar of Frost for massive crits? Then use 2h.
Would you rather have better sustained damage outside of your 45second setup? Then use dual wield.
Dual wield actually has more burst right now. Two handed build has a bit more sustained damage if you stack mostly haste. However, if you want to go full mastery build, I would say run dual wield all the way. I play two handed on mine because it allows me to also play unholy if I want to. Just know that if you do decide to play unholy in the future riders of the apoc unholy stacks haste since the minions aren’t buffed by unholy mastery anymore. And then if you go San’Layn it allows you to stack mastery since there is no scaling issues.