so what is the advantage to these...more durable or something else?

It flies much faster and is more nimble and agile. I've been flying 45mph.... Sounds a tad bit different too, more of a brighter sound, than the warmer sound of the stock ones. I flew out 1.25 miles out to film sailboat racing and it performs like a champ.

they could be a potential for increased risk to the dreaded stress cracks at the motor mounts.  I have flown about 20 flights with the stock blades. I then started using the carbon blades and within about 5 flights I have one stress crack.  

DMB2015 Posted at 2015-8-4 09:22
they could be a potential for increased risk to the dreaded stress cracks at the motor mounts.  I ha ...

that's possible， cause those ones are not as soft as plastic ones, so  the give more stress to the motor mounts