I never had one that didn't run smooth new. never crashed cause one acted up, but i never ran one that broke a prop. if the tip touched something, it got a new motor and that 2814 swap was less than $20. Great for FPV but i wouldn't use them profesionaly. I just recently threw away 17 of em i went through in the last year. They all flew, woulda been fine on a plane, but jello free haulin butt fpv took perfectly smooth motors.
Now that i've been around a bit, the difference in how a bearing wears in a real motor and how it holds the slop out is the main difference i see in higher end motors. the suppo doesn't have a bolt on adapter = bad and the motors don't have snap rings at the bottom so you gotta deal with one of them big ol collars with set screws right were it mounts.
love the way they sound in this clip,,,,,,, all you hear is a slight buzz from 4 motors and a whole lotta wind