If you're not doing mythic raiding you can do well with unholy. Or that's my experience. I mostly do heroic and normal raids and I'm usually doing above average, which I'm fine with and my guild is fine with. I'm definitely beating frost DKs who can't play well or are playing the mg build. I don't have bracers, currently running cloak and trinket and I'm only 894 ilvl without set bonusses. Granted I tend to parse in the 80% - 100% range depending on RNG and the fight.
For M+ there's nothing wrong with unholy. We do good to great aoe with very little effort and while our single target isn't the best, we do enough.
For Mythic raiding you'll need to play extremely well to get the same numbers that frost gets (and the frost dk will probably have to be less skilled), you can still raid mythic if you can find a guild that doesn't force you to be frost, but you won't be the best dps. (This is from other people I've played/talked with's anecdotal comments)
At the end of the day you have to play what you enjoy and find people that "allow" you to do that. I hate the current frost playstyle. So I'll stick to unholy. I've found a guild with which I can reliably clear heroic NH and they have no issue with me playing unholy. Granted I might just be a weirdo as I was playing SV hunter for a month or so after I quit tanking on my druid after we cleared NH HC.
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Also just a heads up, no one will take you seriously if you use Skorp as a reference for dps measure.