New BDK here. Wondering what stat to stack for best tanky feel?
Generally speaking, both are your best secondary stat to go for. Versatility takes the slight edge over Haste. Stack just enough haste to reliably use Death Strike. (Ie having enough runes to get enough runic power to have Death Strikes ready when you need them)
After you get comfortable with the rotation/spec/play style, then you can start stacking versatility behind your haste, and hopefully over your haste once you’re more comfortable and get some decent gear where you can take a hit and not freak out that your health dropped.
Just so you know though, you’ll never feel “tanky” as a DK. DK’s play style isn’t about mitigating the amount of damage you take from each point of damage. It’s about healing back the damage you do take. On a 1 for 1 basis, a warrior is going to take less over all damage than a DK. But a DK will be able to heal through said damage while a warrior can’t.
So you’re always going to see your health spike up and down. So as far as “best tanky feel”, stack Versatility, and watch the health go up and down. Otherwise, if you just want to feel like a brick wall, you might want to consider another class.
Haste is so good more runes more runic power. Verse makes each death strike heal more as well as your dots tick for more… which heals more. I have about 22% haste and still wish I had more half of the time. That said my verse is barely 5% and every point of haste will be stronger with more verse behind it. My mastery is way too high for my tastes and is going to be the stat I try to offload as much as possible from here.
Pretty well what the poster above me said. Haste till you feel good then verse is the general idea for nearly every tank at the moment. Some make better use of mastery and crit but haste verse are pretty well the master tank stats always.
Also even though you dont ever truly feel tanky like a mitigation tank the nice part about blood is that the harder you get hit the more healing you do. I dont think its exactly proper to compare a DK to a monk but like a monk our ability to effect our damage taken largely relies on how much damage is incoming (and we dont suffer from the death by a thousand cuts). Even though yoyoing HP bar is nerve racking at first just remember your ability to push high HPS is largely due to that second part of the death strike description.(heals for 25% of damage taken in the last 5 seconds). Each heal is way bigger when you are getting slapped. The key is to be consistent in when you are healing and weaving your CDs reliably and consistently for your healers. Dont waste all your runic power sniping out 3 death strikes back to back and causing your healer to overheal you because in 5 seconds when you are getting hit by that tank mech again you wont have 3 death strikes and your healers are used to not having to save you. But eventually they will have to and if you have been sniping them all day before that its hard to blame them for not knowing this time you dont have the gas for it. You cant blame them when suddenly you die and they werent frantically spamming you because the last 4 times that mech came out and they tried you sniped it all.
Keep it consistent and allow your healer to get more of a feel for what you need. That right there will do way more for your precieved tankiness than any combo of secondaries.
Thank you all for the feedback. Very we written posts. 
Item level trumps secondary stats. With that in mind you will eventually get gear with both haste and ves on them.
You may want to focus more on vers. Most blood players that i know stacking vers over haste. It gives you a little bit mitigation than haste.
Vers>Haste, but also remember that in many cases you should be equipping based on I level. Crit’s value is actually very good in M+ because of the amount of autos you take (more parry from crit) and crit is also the best overall for damage. Mastery is probably the worst of the stats.
Also, remember that DK azerite are awful and you should almost always choose the least dreadful DK azerite in tier 1, then the generic in tier 2.
Crit is RNG based and it isnt very good. Vers is far better bjorn.
Most of the gear generally will sacrifice vers for crit, whereas you can get vers and haste gear.
Of course ilvl is king but you can go full vers haste mode.
Forgot, higher ilvl will also naturally give crit too.
Im not saying vers isn’t better then crit for survivability, but crit still has a place as a defensive stat in mythic plus. It is also the best stat for damage, which if the content you are doing is trivial or doesnt require more tankiness, should be what your gearing towards.
Still rule, of thumb is always: I level>Vers>Haste>Crit>Mastery.
Ah, I am in full agreement there. It is a shame mastery is such a garbage stat outside of extreme ends.
I believe the only time ive found it useful was when I had tradewinds, and had a 100%+ mastery during orgozoa.
300k shield is particularly good.
My DK feels the pain of having way too much mastery -_-
Maybe they should make DK mastery scale armor given by boneshield. Might make them feel more like sponges rather then soggy paper especially for the first 10 seconds of a pull.