I replaced my Pa800 with the Pa900 – then to a pa4x. Because of the weight I now have a Pa1000, which is very closed to the Pa700.

If the Pa700 is new, I would go in that direction. The Pa900 was a good keyboard, but it has years behind it.
Even if the Pa700 is used, then there is no contest.

But ---- none of this makes a difference. Like Donny said: It’s what sounds and feel good to you. You should listen to everyone, but the last choice is yours. If there is not a big price difference, I would buy a Pa1000, it offers more.

Its fun getting a new keyboard, John C..