While I would be happy to see either if these scenarios play out, I believe a reboot would get more life out of some of the most popular X-Men characters.
Hugh Jackman is moving on from the Wolverine role. Same with Halle Berry and Storm (who I never thought fit the role anyway).
The X-Men need their own .mythology within the MCU. The Fox X-Men film mythology has gotten too expansive to simply intermingle with Marvels rapidly expanding universe. It would become very convoluted very quickly.
As for the F.F., I'll have to withhold my opinion until I've seen it