I like the Nickel strings on my Dingwall Super P/J and Super P. Very even tone from bass to treble. Has a 'softer' feel and sound to me. Seems to fit what I hear in my head for a P/J and P bass.
I agree with everything reddavid said. When I received my new Super PJ 5 I thought I would be changing the nickel strings right away like I did with the SS strings on my Combustion and ABI. They are still on the bass after 2 months and they are still growing on me.