The Note 8 can go brighter under the overdrive thing on auto brightness. But the iPhone can go brighter on manual setting.
Apple gave the specifications to Samsung. They want a brighter screen. But we're talking AMOLED here, brighter means more susceptible to burn in. Basically, the iPhone is cranking it up to 500/700 nits, more than 50% of screen limits. The Note 8 goes to 400/1200 nits, less than half. Less strain on the LEDs.
The iPhone has a more color accurate screen though, even on basic mode. To date the most color accurate screen Samsung has launched based on displaymate scores is the S7.
Honestly I think we're in for a whole lot of new iPhone users with burn in experiences.