Their comments (spoiler warning!):
They played for 16 hours and got about two thirds through the story. That time does include "a bit of PvP and strikes" and adventures.
"Destiny 2 is not a grindfest at all"
You start with absolutely nothing, no power.
Progress is a lot better than in D1.
Mentions you unlock different things at different levels.
He didn't have his sparrow yet at level 20.
Armor doesn't get cool until the endgame.
Talks about Titan (the planet moon). One of the locations is an abandoned resort. Game looks absolutely stunning.
Music is also amazing, apparently only 4 guys at Bungie are responsible for the music.
Zero complaints, except maybe you have to start all over.
(Obviously) they haven't played anything of the end game. He was told the (end)game would unfold "like a flower" once you finish the campaign.