Finally finished binge watching all ten episodes. And whatever minor nitpicks I might have, they really are minor: It's not only compelling and well framed drama, but it really does succeed in creating an alternate timeline that feels real and lived in. I can't think of a single alt-history adaptation that has succeeded like this one has. Yes, we all know an Axis victory is damned unlikely, even with an early P.O.D.; one with Nazis and Japanese(!) occupying most of North America is even more remote. But that's the source material, and on its own terms, it's coherent and plausible.
And what an ending (for Season 1). Season 2 has a tough act to follow.
For the monent, just two minor historical nitpicks (spoilers):
1) It is odd that Berlin, Volkshalle aside, does have a different look than what we'd expect, given that a) there are loads of images of Speer's models and drawings so readily available, and b) Spotnik's team went to such tremendous lengths to get so many little things right. But it's not implausible that Hitler could have altered plans after the war was over, or that Speer might not have survived it. Even for all that, the monorail design looked a little too avant-garde for Hitler's taste.
2) The Hitler of this timeline looks too healthy and self-possessed. Even with a war that ends early with a great victory, Hitler was already on a steady health slide that would have left him in poor shape by 1962, if he lived that long. Perhaps he never gets addicted to drugs in this timeline?