Just finished the series and my overall opinion is that it was... Ok. There were some great fights and really cool lore around the whole witcher universe. My biggest problem was pacing. The character's motivations and feelings just felt very rushed without much cause. Overall it ended up feeling more like a teen fantasy drama than anything.
But there's also things to enjoy. Fun fights, good music, cool lore (if you haven't read the books) and Michelle Yeoh. She's great in everything.