Overall it's relatively entertaining. It's much better than the post Clarkson Top Gear on BBC but The Grand Tour ins't a patch on the BBC Top Gear with Clarkson. But it took years, possibly decades to get the BBC Top Gear to where it ended.
TGT feels overly forced, scripted, wooden. The actual scenes in the cars are great, and the things they get upto, but in the stuido it's cringey. I personally found it borderline unwatchable and skipped most of the chat. They're ultimately not actors and it shows.
I'm well aware that the BBC Top Gear with Clarkson was scripted but it was genuinely funny at times, and didn't seem acted. In TGT it's like they're trying to be a comedy act, a show about them 3, with some car stuff added. It should be the opposite way around.
It's the first series, I expect more, and I expect it to get better.