Yeah, I too experienced sibilance on the Noble 3 during my auditions with them on separate occasions. It was otherwise a great sounding, fun IEM. If only I could get used to that treble spike.
Anyway, are you interested in other Noble IEMs? The Noble 4 may not be your cup of tea, but the Noble 6 is pretty good. Granted, it is a lot more expensive than the 3, but it is a worthy purchase.
Congratulations! Welcome to the Noble family.
Yeah, the K10 is impressive, indeed. By chance, what reprint did you order? It's good that new owners have the Lookbook to guide them with their decision; it's a thoroughly useful tool!