By all accounts the pax thought it was a normal bumpy landing.
Which I think, that whatever the technical reasons for this accident, reflects very highly on the skill of the flight crew. With very little time to react, and sub-optimal thrust, the SFO appears to have still managed a reasonable flare to touchdown, resulting in the "heavy" landing as felt by the SLF, but not heavy enough for some to realise it was a crash!
I also think that this incident does not say very much about the strength of the 777, and comparisons to the A340 run-pen incident are meaningless. The 777 touched down in apparently the correct landing attitude (or close to it), taking the heavy landing on parts that were designed for it. One MLG punched into the wing, the other was ripped off - presumably by the additional drag afforded by the grass, which I suspect also contributed to the NLG collapse. The A340 accident was totally different.
Unless we have like-for-like data (please, no!) to compare, it is a dangerous precedent to set comparing fuselage strengths - yes, the 777 stood up well, but this is only a result of lots of factors, beginning with Boeing's design, and ending in the SFO's flare, touchdown, and rollout (although I imagine he didn't have a huge amount of options left during that phase!).
Thanks guys for the large number of factual posts - the others we can always skip over.