Its fun but not great. Last AC game I played was Black Flag which I thoroughly enjoyed many years ago.
Valhalla struggles on many fronts. Its storytelling is kinda poor. I find it somewhat boring, characters are a bit uninteresting, voice acting has moments of being not good, and the writing can be iffy--such as a character may completely contradict his choice or ideal many minutes later that doesn't really make sense during dialogues.
But the story can still be passable and maybe some may enjoy it. The combat and movement mechanics...this is where its very poor. I just came from Ghost of Tsushima and can confidently say that Valhalla is a major downgrade from that game. And its saddening since I was a bit hopeful with the Viking era. Combat is a bit clunky and parkour is....kinda atrocious. You have the ability to climb virtually everything which is cool on paper and complex but implemented poorly.. Its a struggle to get your character to move in the direction you want them to while climbing. This makes for slow and clunky assassinations and exploration. Compared to Ghosts that uses a more old school parkour design where you can clearly see what can be climbed and is much more intuitive. Leading to smooth gameplay and many times, very cinematic kills. And once you become a veteran player, its super easy to do by instinct.
Also tons of issues with regular combat (poor balancing, stats & mechanics broken, horribly overpowered, etc).
Final verdict, Valhalla would be worth it on sale. It could learn a lot from Ghosts to improve its combat and movement mechanics which really hold it down at times. Story, that becomes subjective but I found it to be iffy. Plus, there are definitely many bugs that are sometimes a nuisance--none that are gamebreaking that I have ran into yet though.