Well, they looked like a pretty poor idea in November 2008 (a year after inception), especially the SPX/SX5E/NKY worst-of basket at that moment it certainly looked like a lose-lose situation for both Berkshire and the dealers...
I knew that specific case but not aware BRK made most of their profit selling puts then and now as he/she said?
Well, it was a good trade at the time, but with the change in their margin agreements that ship has sailed (their 10y CDS is with 90 handle at the moment anyway).
I thought they were 100-year options. The counterparty is a fool, that's for sure. Even Taleb in the AMA says he sells ATM options.
I have first-hand knowledge of these trades No, the maturities were reasonable, from 10-15, though the sizes were scary. Counterparties where fools for other reasons. Unlike a few other famous option trades (like the MS corporate option trade), these were easily hedged and vol risk was laid off (there usually is a fair amount of demand for long dated vol, mostly by insurance companies). However, most dealers did not take into account a garden variety of risks that were introduced by the combination of non-margined nature of the trade and the really large sizes . That's where it got hairy.
I think the total notional was maybe around 30 yards spread across 15-20 dealers. It's impossible to translate that into anything like a leverage number because the firm itself is so correlated to the underlying.