I didn't see either mentioned in DCRs review but I can confirm that there are no cycling dynamics.
F6 Pro
255
But better news is native Trainer support - this allows your FE-C trainer to be controlled via the 255 with no need for additional apps - so a Garmin Suggested Workout will be fully executable on the watch as will other workouts you may create.
So overall power meter support seems solid - I will only miss the sitting / standing cycling dynamic (from my F6)
So far I am quite pleased with the 255!!