Normally I'd say the lineup. But if NX isn't as powerful or in the same ball park as NEO and Scorpio, they'll be right back in the same place they were with the Wii U for 3rd Party Support, so I'll say Power.
Hardware Comparison Threads:
Current Thread
Is Hardware Getting TOO Powerful?
Older Threads:
PlayStation/Xbox/Switch: 2022 Edition
PlayStation/Xbox/Switch Hardware Battle: 2021 Edition!
PlayStation 4/Xbox One/Nintendo Switch: 2019 vs. 2020
PlayStation 4/Xbox One/Nintendo Switch: 2018 vs. 2019
PlayStation 4/Xbox One/Nintendo Switch: 2017 vs. 2018
PlayStation 4: 2015 vs. 2016 vs. 2017