Maybe a contrary opinion, but Episode 3 is where they hooked me.
I have had the first book for ages, but never really read it. I think this series suffers from its episode count. The books (from what I have flipped through) are very dense with detail. Very different from Twilight, although I agree, the basic story beats are scary similar (I hope we don't get a werewolf love triangle though!) The books are largely told from Diana's POV, and I think that really helps the character. Here, we just know what we observe, and we are tainted by the actress's performance.
I LOVE Matthew Goode. I may or may not have rewatched Chasing Liberty a number of times, years ago. 🙂 So I was all in on this, even though I agree, he doesn't exactly resemble the description of Matthew in the book. (I am picturing someone taller and broader, more like Christopher Reeve.)
Teresa Palmer's line delivery, however, reminds me (unfavorably) of Sophie Skelton (Bree) on Outlander. So I think that maybe, for some actors, the need to focus on the accent gets the better of their acting. Palmer's nonverbal moments, as mentioned above, are pretty good. But that Episode 1 scene where she gave a lecture? OMG. No gravitas whatsoever. This is a top-notch professor? I just don't buy it - and unfortunately, I think it's the line delivery.
I know a little more about Outlander, so I know that they had a hard time finding a) an actress who resembled the leads, and b) a UK actress because of their budget. What was the constraint here? Why couldn't they hire an American to play Diana? I mean, heck, they didn't even hire a Brit!
But just like I was initially in on Twilight many years ago (don't judge - it was before the Eclipse book even came out!), I'm sold on this now. Can't explain it. Definitely reading the books though. I have too many questions - like what is the deal with the young couple and his mom? (Again, longer episodes would help.)