I say this as a person who watched the 2007 version and was very deeply impressed by it, this version is worth watching, but only if you like Nakai Kiichi's acting. He is the one who carries the drama.
As for the other two leads, I never liked Mukai Osamu's acting so his scenes (except for the final one) felt like a drag to me. Same with Uchida Yuki.
For people who have neither watched the 2007 (KimuTaku) version nor read the novel, I would recommend:
1. if you don't want to spoiled story-wise, watch the 2007 version first. I just felt like the 2021 version reveals too much from the beginning. That kind of spoils the impact at the end. On the other hand I have read some reviews claiming that the 2007 version felt rushed near the end. so ymmv
2. if you don't want to be spoiled acting-wise, watch the 2021 version first. Nakai Kiichi is good but even he cannot carry the two less talented leads ( Mukai < KimuTake and Uchida < Kyoka Suzuki)
As for the other two leads, I never liked Mukai Osamu's acting so his scenes (except for the final one) felt like a drag to me. Same with Uchida Yuki.
For people who have neither watched the 2007 (KimuTaku) version nor read the novel, I would recommend:
1. if you don't want to spoiled story-wise, watch the 2007 version first. I just felt like the 2021 version reveals too much from the beginning. That kind of spoils the impact at the end. On the other hand I have read some reviews claiming that the 2007 version felt rushed near the end. so ymmv
2. if you don't want to be spoiled acting-wise, watch the 2021 version first. Nakai Kiichi is good but even he cannot carry the two less talented leads ( Mukai < KimuTake and Uchida < Kyoka Suzuki)