Speaking as an owner of the P and all versions of the 7, I'd vote for the 7s, closely followed by the P. You will probably be very happy with either one, and will probably find yourself metering with a hand held with either camera. The meter on both of my 7s' isn't what I'd consider accurate, and is not the main factor in the choice. I like the VF, and the ability to change lenses without the nuisance and bulk of a seperate finder. The camera is also very well built, and will stand up to hard use. The same could be also said for the P, with reservations on the VF. Both cameras would probably benefit from a CLA, unless one has been done fairly recently.
The ideal choice, of course, would be to own both of these fine cameras. They complement each other very well, and I like to use a 7s/w 35/2 and the P with the 50/1.2 as a combo. They both fit in an MClassic bag with room for a meter and plenty of film + filters and whatever. Carry just one camera and you've got room for a small drink and a bologna sandwich.... or something.
Harry