Looks like the review embargo has lifted, I've seen several reviews pop up today.
Reviews:
https://www.engadget.com/amazon-kind...0.html?src=rss
https://gizmodo.com/the-new-kindle-p...-re-1847863029
https://www.theverge.com/22745670/am...e-reader-books
Picture comparison with the 2018 PW:
https://gigazine.net/gsc_news/en/202...te-comparison/
Hopefully there will be one with a direct comparison of the Voyage so we can compare screen contrast in a picture at least.
Edit: I'm not going to post this in a new comment since this is apparently a controversial thing, but initial reports are that the PW2021 still doesn't have quite as nice of a screen as the Voyage although it's closer. I compared my Voyage with my PW4 and notice a difference, although I wouldn't describe it in as stark of terms as others have.
https://www.reddit.com/r/kindle/comm...ade_my_voyage/