P or J whats the diff?

Hello all

I have just been loving my Godin 5 and have been looking at all the others out there 4-6 string so far.

One thing I do like is the slim neck of a 4 string and think I will pick one up probably sooner than later. This brings me to my question, whats the difference between the P and J. Most sales guys tell me its just the pickups but I think its more than that.

For a Metal, Blues do all bass which is better?
What are the best $700 to $1000 4 strings out there with active electronics?

Bev