Absolutely, insanely awful, if you are hoping for a faithful adaptation of the books- there’s a callous disregard for the source material that is infuriating for the hardcore fan.
Slightly subpar if that’s not your priority- the costuming is not great, and often pulls you out of the viewing immersion such an epic fantasy should offer. The characters, for the most part, aren’t overly compelling or likable.
It’s more akin to MTV’s failed Shannara adaptation than HBO’s Dune masterpiece.