Not much changed from the previous seasons, but I decided to make an updated guide anyway. This build is used for Torment farming but with slight modifications can do well in solo GRs too.
Feel free to watch the video for some additional info and a preview of how strong UE DH will be in the new Torments.
Gameplay is very simple, just keep up your Focus buff with a generator every 5sec, then vault around and Multishot stuff until it dies. Keep up your Harrington Waistguard and Goldwrap buffs, be resourceful with your discipline and that's pretty much it. You should try to farm at a Torment level where you can kill everything in 1-3 seconds, excluding the RG.
Build (Cold vs. Fire MS)
In the past Multishot - Arsenal (fire rune) was generally considered the best, though that has changed. What makes the Wind Chill (cold rune) superior is the its slow effect is applied before the damage is done (unlike Thrill of the Hunt or Iceblink for example), and this means you can fully benefit from the Cull the Weak (20%) / Bane of the Trapped (~40%) multipliers on your first attack. If you combine this with Ambush (40%) you will almost certainly bring every monster below the Dead Man's Legacy treshold (50-60% hp) and hit it twice even on the first attack, which will usually result in a oneshot kill on basically any trash monster and sometimes even on elites, something that the fire rune fails to do consistently when the rockets are not hitting the targets you want. Counting the AoE component alone, cold will do roughly 60% more damage on the first attack compared to fire, and this is not even considering the added bonus of 8% crit chance you get from Wind Chill, which makes these oneshot-crits much more consistent. Generally you can expect to only need ~half the amount of attacks to deal with most stuff in a rift, though you will spent a couple more seconds on the RG and occasional elites here and there.
Full UE set with Yang's + DML, F/R and Harrington for more damage, Nemesis Bracers to cut time spent in rifts. Obviously the crit stats and cold damage are preferred, after that stack CDR (first priorty) and RCR (second priority). If you go with Goldwrap, you can completely disregard any defensive stats, otherwise try to stack some vitality on items where you don't lose very much (helm, shoulders, quiver). The preferred amulet would be a Hellfire Amulet with cold, chd, cc, socket, as a fifth passive I suggest Single Out, Sharpshooter or Hot Pursuit. The Dead Man's Legacy quiver has been reworked and now rolls with up to 100% Multishot damage, a huge buff to the set. The 4piece (from 20 to 60%) and 6piece (from 15 to 20% per discipline) bonuses got buffed, too, and Vengeance now increases our damage by 40% as well.
There are some things you can change once you get stronger or in case you dislike parts of the build. For the cube you could run In Geom in the weapon slot, that way you will have much more discipline to vault around, but need high kill speed. In the armor slot you could switch to Pride's Fall for more consistency, Warzechian Armguards if you have trouble keeping up. In the jewelry slot you could run Convention if you're too weak, or Obsidian Ring to help with cooldowns.
I definitely would not recommend to run UE in high Greater Rifts because the set is just far too weak to compare, but if you want to do it anyway, the cold variation should work fine in groups, fire would probably still be the preferred choice for solo. Just stack a little more toughness and replace the movement speed / utility stuff with more damage.
D3planner link: http://www.d3planner.com/863254045