I tried both, the NJ4's have much more flavor and character. Warm, bump in the mids without an overly harsh high end. My favorite J pickup ever.
I gave the Aguilars a spin. They were similar to the Nordy's but without the flavorful bump in the mids. They were very "flat" I would say... almost boring flat IMO. They were warm, but no real "character" in the mids.
Just my opinion.
Sadowsky | Nordstrand | TC Electronic