5050s are apparently OK provided you don't get the basic ones.
However, they're made by crank bros.
So they'll last about 2minutes before falling apart, and rattling endlessly.
I'm afraid but I must disagree with you, mc.
I've been abusing of a pair of 5050s XX for about 6 months now, been hitting roots, dirt, rocks and bone to the point of snapping some pins off the pedal and they run as smooth as new! The bearings roll smooth and without any slack... and still no maintenance done (and I'm on the 187pound league

)
But hey, that's just my experience.