Which Would You Rather?

This.
And this.

(Also either of those coins is likely to be far too expensive for my collection, which is yet another reason for me to avoid them, but let's ignore that for the moment. Maybe I just got a remote job for a US company and now earn $10+ per hour.)

Assuming that I do, in fact, need one (for example, if this particular date or type is rare in circulated grade and has counterfeiting problems that mean non-slabbed coins are suspect[1]), I'm probably going to agree with Jbuck's reasoning and take the 66 - I could hardly care less about CAC; of course I don't care much about PCGS either, but if I do end up with a MS grade slab I'd rather take the higher number.


[1] limiting this to coins that are common in grades as low as MS-65 (which excludes, for example, Platinum Eagles), the first thing that comes to mind is some kind of classic commemorative, but there are probably other options I couldn't think of immediately

I would take the MS-66.

Because you said all the coins looked the same. So that means the gold cac one is just about the same grade.
I doubt it would come back a MS-67 unless you're sending PCGS or NGC thousands of coins.

Matter of principle, I just don't buy slabbed coins. For me if coin is slabbed it doesn't exist.

Buy the coin, not the holder.