Well... none of the above is "best all around" but if you just want my choice I'd have to go with duress. Duress in an ethereal armor that was socketed with the socket recipe in 1.11 can be very very nice on a merc.
But on different characters, each of the four armors listed could be best for that character.
It really does depend on what type of character you have. For example a caster would not benefit much from Stone/Duress, but would from Smoke/Gloom. That is if you are in need of resistances. Were I to pick one then Gloom would work out best for casters, Duress for melee characters and either Duress or Gloom for ranged characters.
But then again there are better options for all of them depending on what type of build you have. For example I'd prefer a Vipermagi on my casters instead of Gloom.
In my opinion, Gloom is superior to both Stone and Smoke, unless you're going to PvP and need the FHR from Stone (then again, if you PvP, you'd need to try to get your hands on Fort/CoH/Enigma etc). Smoke gives massive resists at a dirt cheap price, Stone gives a hefty amount of defense. Gloom gives both, and only very slightly lower stats than the uni-functional armors and adds sweet crowd control! It's the most expensive among the 4 you listed, but still very attainable.
Duress is strictly a melee armor, and although it's very useful, I don't like it because of the unimpressive numbers (and also because I still play vanilla 1.10). If you don't have resist problems, are not MFing and not into high defense (e.g. questing Fury druid with a high-res Tomb Reaver), Duress should be your choice!
Not to pick a fight or anything... and not to say there's anything bad about what you're doing here... but...
I'll say it: Next time you post, could you obey a couple rules of forum etiquite? First off... pick a more descriptive subject. This one is pretty vague. Secondly... we tend you use complete sentences here, and avoid stuff like "ty for ur answers". Also... the over abundant use of XD and really distracts from your otherwise interesting posts.
Try to give us as much information as you can next time... don't make us guess that you're playing a WW Barb.