OK, so my main is on the new archetypes, and so the time had come to run Dark Hunter. I'd just done a tempest ranger life on my alt, so I thought I'd try to use the new enhancement tree instead, to check it out. We (three guildies) ran mostly on r4, and sometimes even down to r2 because we're slackers.

OK, what kind of build did I use? Dex based tabaxi (to get evasion), with a tiny bit of int to get my trap skills up a little. Used scimitars (had the old vorpal ones from Crystal Cove still).

Base class
The sneak attack dice are nice.
The limited FEs are annoying, but can be somewhat worked around with universal trees.
The curative admixtures are both good and bad - you get AOE healing, and with a better version in level 4 spells. On the down side, they're slooooow to cast (quicken doesn't work on them), and had the usual targeting issues that annoy me.
Having trap skills is awesome.

DH enhancements tree
Wolf: As always, companions are mostly useless to me. I took all upgrades in the tree for it, and have all the old PLs, but it still dies quickly and does little damage. Having a lever puller is always a good thing, though.
Sneak attack training: More SA dice is great, I love it.
Bleed the weak: Combined with the upgrade from the wolf line, it can do a bit of damage - but bleeding is a highly resisted damage type, so it's not uber.
Stone's Hue: More PRR isn't bad, and it only costs 1 AP.
Death Attack: I tried this. I really did. When it works, it's great. I love assassinate, I've played rogue assassin several times, and I love it. But the limitation on which targets it can instakill is very annoying to me. The bleed damage is neglible, so that does nothing. And the debuff is pointless in heroics. I really, really loathe this ability. You sneak, get close, and then.... disappointment strikes. Now, if it did something like a paralyze on other targets, then it would still be worth something. And still be different from rogue assassinate. As it is, I got so annoyed at level 18 that I respecced to tempest t5 for the last 600k xp.

Conclusion
All in all, it's OK. I'd probably not use the enhancement tree again, but it can be decent with a normal tempest version- The SA is good and works on everything. Sure, you lose some of the more decent FE picks, but it is not a dealbreaker to me. And trap skills are always great to have.