Holy Grail
You get a shot at it, you probably take it...
The NASA/ESA thing is that ESA is several orders of magnitude less paranoid about planetary protection, and can therefore "afford" a smash-and-grab MSR mission.
NASA wouldn't be allowed to play cowboys like that anymore - the maturity / dynamism thing about space programmes...
ESA hasn't lost any astronauts yet, but NASA is getting quite good at it.