Not very reassuring to me
At this point I would consider it premature to claim this a victory for nuclear safety... kind of like it would have been premature to claim a victory for deep sea drilling when BP claimed a mere 5,000 barrel/day leak. I personally take any industry or government claim with a grain of salt where gauging the magnitude of a disaster is concerned. I'll wait to reserve judgment on the severity until after this has played out.
I'm also not sure why the fact that the plant survived "a quake 5x more powerful than it was designed to cope with" is reassuring. Obviously the disaster scenarios were inadequate and it is thanks to over-engineering that this is not more serious. I would be very concerned about why the disaster scenarios weren't adequate (they should be MORE extreme than what nature can dish out).
Finally, it is an eye opener that 6 nuclear plants are all having cooling issues coincident with this quake. It is fortunate that shut-down procedures, safety checks, containment vessels, etc. have all performed so well, but it's not difficult to imagine any of these breaking down in a case where the facility was not as carefully designed or run. Despite all this, the problems are not simple... Japan is requesting assistance and getting help from international bodies.
None of this spells doom for nuclear power, but there are real lessons to learn. This event reinforces the need for reactors that incorporate passive shutdown designs that do not risk meltdown such as Thorium reactors, particularly as reactor density increases globally.