The Shadow set is very impressive. With mediocre gear and near useless with the skill rotation, I tried and completed a 75 grift in 9 minutes. It was the first time I had tried to run the complete shadow set. It's tough as nails, I think I had 400 million + toughness with my buffs - which are up 95% of the time with just a bit of CDR. Single target damage is mind blowing. Killing T13 RGs in 1-2 seconds. And with almost unlimited vaults, it can be really fast. I've never been very good with vault, but this build makes me eager to learn how to use it properly.
I won't be running seasons this time around but recommend the Shadow build for anyone on the fence.