Hi,
I started with the J-Head - and had bad experience. It was leaking plastik between the peek part and the nozzle. I tried to fix it and killed the thread. Changing the nozzle is a pain.
The I bought the E3D-Hotend with a 0,25, 0,4 and 0,6mm Nozzle, put in the Extruder and: I just forgot it! It´s printing without any problems since 3kg of PLA and 1kg of ABS. Even idling when it is heated up doesn´t lead to jamming. Sorry I can not help you with the comparison, one thing I can say: you will be satisfied with an E3D!

Kind regards
Manu