blood subspec 14/0/57 (with reaping)
frost subspec 0/17/54 (no reaping)
How did it look?
I've already talked about the blood subspec. It was very solid! I was able to put in a top-10 World of Logs parse worldwide, and generally had both solid single-target and aoe dps. As you can see from the Festergut screenie, I did well, and helping me was very solid raid dps (including the top-10 fury warrior and excellent lock). Overall, I'm both comfortable and happy with the spec.
Recount dps actually lower than the WOL parse (unusual!)
How about the frost subspec? I didn't practice with it much. The only 'major' difference with the spec is the absence of reaping, which means two more blood strikes, and one less scourge strike - and therefore a tiny bit more gcd constraint. So, I was surpised and dismayed when my dps seemed quite a bit lower - especially given the 5% increase in the ICC buff! The other DK was solidly beating me on most fights.... and I was actually much lower on Festergut and Rotface than the previous week. I was about to give up in disgust when I discovered my own absolutely foolish mistake! NO FREAKING BLOOD PRESENCE! So, I have to laugh at myself. I don't have a good comparison on the tank and spank fights. :( However, once I made the correction, I was able to see frost subspec in action, and it seems quite comparable - as reports have said. You can see from my parse below, it wasn't bad even though I spent 80% of the night without a presence (add about 15% to my total and I'd have been at a more respectable ~10,600 overall). I also did one tank and spank - Toravon - and I was pleased. My recount dps was 12,229, good enough for top-20 worldwide on WOL (sorry, no screenie, but you can look me up on WOL).
So, which spec is better?
From my very limited sample size, and my tremendously flawed execution, I'm still reasonably comfortable concluding Elitist Jerks are right on the money. There is very very little difference between the two specs. EJ folks are arguing that for a non-proc weapon such as Cryptmaker or my Shadow's Edge, the blood subspec is better, and with a proc-based weapon such as Bryntoll or Shadowmourne (I don't have either), frost subspec is better.
Personally, I'm going to run with the frost subspec the rest of the week, and see how comfortable I get.
But in general, you may decide to subspec either of the above. Follow the EJ suggestions, or subspec into blood simply because the additional threat reduction is handy (I did notice I was tanking more trash than usual last night - but more careful target-switching should help with that).
Either way, Unholy is looking good!
Next week I plan to go blood: I'll probably put in 5-10 armor pen gems and give it a try!