Help me choose! Blood DK or Tankadin?

[Tazienne]

I'm going to post this in both forums as I'm hoping to get responses from both sides.

2 weeks left till MoP drops and I'm in a spot that I hoped I would have solved by now.
I am a Tank. I've been one for over a decade now through various MMOs and I know its what I enjoy.
I have 9 classes level capped for a total of 12 characters, but its too many to start an expansion with and I face this every time. I need to narrow down my tanks, in particular, because its the job that I will be doing first and foremost.

Two (2) tanks is what I want to limit myself to because I'm a mainly casual player and don't have all the time in the world to gear all of them equally.
I know that warriors are not my thing, never have been, even when I used one as my MT for early BC raiding.
My Druid has a lot of sentimental value and, judging by my preliminary testing, will likely gain one of the two open spots. Mainly due to the feel of the CDs and the way the skills work together combined with my love of PVP flag running.

The question I pose to anyone willing to read this far is this: What are some of the pros and cons of each of the Knight classes in your opinion? If you play both, are there skills that you miss greatly when you play one over the other? How does each of them stack up compared to what the Druid brings so that I could cover the weaknesses of my Druid with one of them? (ie. Druids still lack a ranged interrupt unless they use a glyph, whereas both the Knights have it.)

I'm having trouble comparing them with my own characters due to my Pally having significantly less gear than my DK because I did a server transfer and did not move my original Paladin, thus I had to re-level a new one who has been mostly shelved since hitting 85 compared to my DK that I moved over who had been one of my main tanks since Wrath. Since their gear isn't equal (My pally cannot even get into any relevant raids) I can't really compared them side by side myself with only 2 weeks left before I need to be deciding who to level.

I do intend to work them all to 90 and tank along the way, but obviously leveling is no real judge of how things feel in a level cap environment. Also, I am well aware that performance at 85 can be vastly different than at 90, but anything really would be of use at this point since I'm very torn. So, any assistance? Thanks in advance for any willing to read and respond.


(Additional Info): I do enjoy soloing old raids, usually on my DK since that's been the class for it.
As I said, I am casual to an extent. Raiding will mainly be limited to 10 mans, normal likely, heroic if I can flesh out my guild more.
I like the DKs previous feeling of being self-sufficient. When a healer dies in a 5 man, I like knowing the fight isn't over.
Same for when DPS is lacking. The pre-5.0 Druid and DK had great DPS output without relying on Vengeance thanks to multiple DPS cooldowns.

[Malthanis]

You'll have to play them both to figure out which you prefer.

Closing.