For BRK, there are three different valuations: book value, intrinsic value (a range) and market value. The first one has been dropped as a yardstick.
For FFH, there are only two different valuations they look at : book value and market value.
On annual letters, if I recall, Prem W. equals book value with intrinsic value.
It is safe to say that BRK looks more at economic reality as oppose to FFH that sees accounting book value as a significant yardstick in representing economic reality.