I recently completed a JK run with a strangers.
Honestly at the beginning I thought we would have a hard time - One guy had a almost-complete 5* setup (and was dying at every turn, ironically.) I was halfway in 4* and my two other friends were wearing 3* stuff. We didn't have any trouble except for the parts with blast cubes because someone kept shooting them. We all thought we would get out butts kicked by JK, even though we all had appropriate gear and vials and weapons.
But,
We spent about 20 seconds fighting JK. For some reason he reached his first rage mode within seconds after a few (Calibur) charge attacks, and died shortly afterwards.
We were all left saying "That's it?" after he died. We hadn't even used more than two vials of any type.
(Not to mention I got a Brute Jelly Shield drop from a treasure box. :D)
So what's yours?
My best Royal Jelly run ever was the first time I beat him solo. Sadly it wasn't until after the halloween patch, but it still made me smile like no other RJ run before it.