funny thing is. you can't tell all that much by Strava stats alone at all.
Many strava users KOM/PR hunt. ie. seek out specific trails, practice them to death and turn up intentionally when said trail is in it's best condition to attempt to place high on the leaderboard. (or in the case of road riders, pay attn to wind direstion/ride in a group) not saying they're not still good riders just that (even glitch free) Strava isn't always a very fair playing field.
A good rider is obvious when you see them ride.
haha I have waited on wind direction before when me and friend were battling a KOM on the local estimate