Well, I have to say, I'm pretty impressed. Bearing in mind that I play in VR and so my graphics settings are medium at best even with my new PC, I've done a couple of flights now over the updated UK landscape, and IMHO it's really very good.
After the first cloud covered flight I then set the weather preset to clear skies and flew over the Kent countryside from Biggin Hill, following the M25 around and spotting familiar locations (I spent most of my life there, but still failed to recognize the town where my house is
- I shall definitely be going back to see if I can spot it.) before heading up to land at London City Airport.
Then just now I did a flight from Glasgow to Edinburgh, real time, live weather (22 knot winds) which obliged me to fly around the airport and land from the east, flying over what I presume are the Edinburgh docks and the three Firth of Forth crossings which all looked great to me.
Both of these flights were in Cessnas, so a couple of thousand feet at most, and the scenery looks great, the buildings look remarkably good and I've even got some traffic on the roads, which also look really good, remembering that they often just looked like grey ribbons before the updates.
I've also noticed that the runway / taxiway signage seems larger and clearer. I cannot speak for the 'realism' of the airports themsleves, and anyway, because VR I still have AI and airport traffic set pretty low so while they aren't completely deserted they tend to be quiet.
All in all, these scenery updates while they may not quite get to photorealistic, especially in VR, they are IMO very good, and when I fly over places that I'm familiar with either in the UK, or the USA where I currently live, I can spot specific golf courses, shopping areas and roads, and of course natural landmarks, and it's pretty impressive.