Different critters, for sure.
I love them both, and have them both, and I couldn't make that decision either.
If I was to say which one to get FIRST

D), it would be the 1217.
Icon, American embodiment of steel, etc., the most important thing to remember is, its a Fighting/Utility knife. Fighting comes first in that name, for a reason. Its light, comfortable in the hand, solid build, and a very, very versitile blade.
It was my first "real knife" and I will never be without on in my pack, or at the very least, in my collection. There is nothing in the woods that it won't do. Baton, whittle, chop, pry, bore holes, etc. I've done all of it with mine.
Does it have some short comings? Not really the way I see it, I just say it fits all the features that it has and few more.
Is it as tough as the BK2? No, but not much is. The BK2 is my "the knife", you know, the one knife that we all look for? That's mine. If I had only 2secs to pick a knife to take into any unknown situation, it would be my BK2. But just like the 1217, there are some that say it has its limits, to which I reply, "Yeah, what are they?"
Too thick, its a matter of each persons perspective.
Stick tangs are weak, not really, Randall Made Knives has been making stick tangs for years, as well as tens of thousands of other knives that are still going strong, Kabar F/U knives are most certainly one of them.
I say, get the 1217 first, and get used to the feel of American quality, then, get the BK2 and get used to the feel of American ingenuity.
Both will serve you well, and for a long time.
Moose