Finished the season yesterday, without having read the books or played the game. Overall, I would rate it as 'Ok', but it definitely has some flaws.
As others have pointed out, the main issue with the series is, that Geralt is pretty much the only interesting character. I mostly liked the parts with him, but found the Yennefer and Ciri storylines to be relatively boring. Hopefully the three will get to interact more in upcoming seasons - it felt like a missed opportunity to have Geralt and Yennefer share so little screentime in this.
The different timelines did confuse me initally, but once you understand it, it is not an issue.
Looking back at it, my favourite episode would still be the first. The Renfri story was great in terms of introducing Geralt's character (his morality in not choosing sides etc.), and it also had the best action. Also really enjoyed the Striga episode (although I can't really recall what happened to Yennefer and Ciri in that).