I generally see people talking about how safe the new reactor designs are, and how it's a tragedy that people are so afraid of nuclear that they won't let them be built. The reactors in Japan are 40-year-old designs. You can't compare them on the same level. It's like saying that people in favor of nuclear power claim that Chernobyl never happened because 'safe nuclear' == 'never was a reactor that was unsafe ever built.'
Add to that the fact that the other reactors there have stood up to a 9.1 quake with about 600 aftershocks -- ranging from mild to "I'm a pretty decent disaster all by myself" -- A sizable tidal wave and numerous fires with hydrogen explosions.
This could definitely have been far, far worse by now.
You might be surprised to discover that a 40 year old life is fairly standard in nuclear power plants[1], in fact some countries hope to keep their plants active for closer to 60 years. At close to $7B+ investment in just the building phase of a modern nuclear plant and close to 7-10 years construction time per plant[2], the limited lifetime of the plant does start to become a concern in the financial sense though.
I'm not balking at the age and saying that the place is 'falling apart.' I'm saying that they were designed 40 years ago, and that it's possible that we've learned things since then and can build better plants (starting at the design phase). I'm no expert though, so I'm making no claims.