As its own anime, it's honestly absolutely fantastic. Really unique and gorgeous art style that has a look and vibe you don't find in other series. Character designs are all super cool, from major characters like Lord Death and the main 7 to minor and side characters like Justin and Blair. The ending wasn't perfect but was pretty damn great. The main 7 developed really well and their bonds to one another grew really deep. Despite Maka and Soul being the main characters, Black Star, Tsubaki, Kid, Liz, and Patty all have a lot of screentime and great moments, too. There was great character theme songs and background music as well as some of the best openings and endings ever.
As an adaptation to the manga it leaves a lot to be desired, but I'm rating it based on how it is on its own.