I'm currently going through a similar exercise myself...so it's great to read your post.
It's interesting, FFH, BRK and MKL are all business that are predicated on the write insurance premiums and invest the excess float (that doesn't have to be reserved for prudential/payout requirements) model - ie get access to capital at low cost. I was reading something by Buffett the other day that highlighted, in his words, that not all Insurance businesses are actually able to write insurance premiums at a sufficient premium that ensure a float exists - he explicitly stated that he believed that GEICO was great at doing this...two thoughts going round in my mind:-
1) "are FFH and MKL able to sustain insurance returns and thereby give themeselves access to the float better than BRK/GEICO can?"...
2) Putting Point 1) aside, who out of FFH, BRK and MKL have better underlying operational longer term businesses that they have invested in? I don't know the answer to this....and would welcome thoughts.
Even though Buffett is getting old, I'm getting the feeling that I'd rather overweight towards BRK rather than FFH /MKL.
I'm also looking at GBLB - Groupe Bruxelles Lambert & HCHC (Phil Falcone ) -although I'm a little uncomftable about the debt position of HCHC (high)