I've just finished this via on-demand, so here are some comments and observations. Overall, I thought it was a pretty good adaptation. I think the series format helps in places where more exposition needs to be done where a movie would have difficulty with, so I appreciate the slower pace, but at the same time there are a lot of places where I felt they could have done so much more but were restrained.
I didn't really like this version's Lyra. She was a kind of weak point in this for me. It's also impossible to not compare to the movie at this point, but Dakota Blue Richards had a twinkle in her eyes and had full enthusiasm in how she approached things and was very keen on seeing the world. Daphne Keen's Lyra, albeit due to direction, embodied almost none of those traits and almost looked bored most of the time, carrying a blank face wherever she went, hardly a smile. There was no sense of wonder coming from her, and she was less fun to watch.
Lin-Manuel Miranda as Lee Scoresby, as much as I like him as an actor, felt like he was miscast. It's like they just gave the role to trendy actor. So much of the dialogue, at least as far as the book goes, works better with an older character than what we got with Miranda, which is why I felt the movie version of the character was so perfect. Either Jeff Bridges or Harrison Ford would have worked so much better, able to show visually that they're grizzled and well-traveled. He here looked too smooth and clean. And the other thing that disappointed me about him is that in the book he was such a strong instrumental character and his scenes with the balloon were much more important, but here it's as if they didn't quite know what to do with him. He seemed to stand around a lot and talk before getting to his balloon scenes, which leads me to my next point.
I was really looking forward to seeing how they would undertake the balloon scenes, since they were fairly epic in the movie. What we got was fairly minimal via a single episode, and then they skipped the crash landing completely, which I gather is budget related. But in doing that, as someone pointed out, it then creates questions about how Scoresby and Roger survive. So, wasn't too impressed with that. This was one of the places where I felt they could have done much more with.
I thought Ruth Wilson as Mrs Coulter was done fairly well. She even evoked a similar vibe as Nicole Kidman in the movie version, and despite their age gap, they look surprisingly alike, especially the hair and the eyes.
I agree that the bear fight was much better done in the movie. Anyone notice how close-in the camera on this one? In the movie version, they pulled the camera back more to give it a wider more epic scope, at the same time giving us an idea of what they were fighting for, their land and freedom. The camera being close-in on this version was a disadvantage, not only because you couldn't see who was who without their armor, but that it was indoors with poor lighting.
Overall, it was fairly good, and I look forward to the next season. One of my favourite things about The Subtle Knife was the world of the Mulafas. That should be fairly interesting and unique.
I spotted a pretty big technical goof in Asriel's Lab. Though it's been such a common mistake in moviemaking that I find it more amusing than annoying at this point, but it's still a technical goof that had they good science advisors, they'd have been told to set things up differently.
Basically, you have two types of telescopes, reflectors and refractors, both of them getting the images to your eyes in different ways due to the way mirrors and lenses are positioned. In a Refractor, your eyepiece is typically at the bottom end of the telescope, either at an angle or directly out from the tube, looking into the eyepiece and out to where the telescope is pointed at. In a Reflector however, the eyepiece is typically at the top of the tube at an angle, with your main mirror at the bottom of the tube where it catches all the light and the image reflecting that to a diagonal and then at your eye. What they had on the show was a Reflector, but they had it pointed in the wrong direction. Mrs Coulter wouldn't have seen the aurora like were were shown, but a highly magnified floor!

I get the intention they were going for, though. What they really wanted if they really wanted to use it in such configuration was a Refractor.