I have seen a lot of threads in which young players ask about which armors are best to play in; there are several answers but lets look at the most common ones.
Chaos Cloak and the BK set gives a very nice damage boost but lets face it, you can't tank status hits like other armors.
In this game it is statuses not type damage that can ruin you, with Chaos Cloak/BKset you get set on fire or shocked then it is pretty much over for you. Poisoned, frozen (for Chaos), or cursed and you are out of play for ages.
Not really safe choices for new players (though if you have a BK set you probably aren't new).
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Next we have standard class boost sets. Shadowsun, Skolver, and Volcanic Demo all provide good damage or CTR boosts and a single reliable status resist.
They also don't come with any status penalties which is nice, but they only offer one resist and a damage/ctr perk to only one weapon type. These armors function as a middle ground for new players, it helps them learn how to play with a bit of extra power but doesn't punish them terribly for making a misstep.
(Specialist armors are in this group as well but offer more status resists but are very specialized)
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Last we have the hyperdefensive sets; Dread Skelly, Grey Owlite, and Mercurial Mail. These offer a hefty bit of damage and status resist (in the case of Mercurial mail extra evasion potential). These sets don't offer any damage or CTR perks but are forgiving to those who receive status or hits from monsters.
A major flaw in SK's PvE is that the statement "the best defence is a good offence" more or less holds true. While Chaos and BK gear aren't really fit for newbies who might get hit a lot, there's no major benefit in getting the most defensive sets as they don't have that much of an edge over class sets in terms of defence while they also leave you comparatively weak, which strips you of your ability to make good use of being able to take more hits.
Personally, I think I'd mostly recommend class gear to new players. Divine Veil is pretty decent as well. I also find Chaos very recommendable to people who have already assembled a good first 5* set, as they can get one piece and gradually walk into the realm of status weaknesses to make it more manageable and easier to control. If they are not comfortable with one piece of Chaos and one class piece, they can go back to a full class set. If they are doing well in a Chaos/class set, it's viable for them to make the full Chaos set.