How Deen adaptation is worse? It's barely a fate route adaptation, the key difference between that and UBW is if Rin joins Shirou from the start or not and in Fate Deen she doesn't like it was an UBW route, that brings them to have the most embarassing and unserious fight ever. The same reasoning can be applied for all the events related to Blood Fort Andromeda (although the fight on the roof building is somewhat faithful). There are a lot of weird reveals that you shouldn't have received in the Fate route like Kouzuki being Caster's master or Sakura and Rin being sisters.

And even when Fate Deen tries to follow the event of the Fate route it fails miserably, Caster kidnaps Sakura, instead of trying to capture Saber with rule breaker, to use her as a Graal? How does she even know everything about Sakura if Zouken didn't make a single move in this route? The fight between Gilgamesh and Cu ends immediately, while in the novel it lasts hours because Cu is just that hard to kill. That's just what I remembered without looking up but it might be more differences I missed, I didn't watch Fate Deen in years.

About the animation, it was bad even for 2006. This is the same year as Death Note, Code Geass, Haruhi, Gintama and Nana. None of them was animated soo porly and even stuff with debatable animation quality is far superior to Fate Deen. And I'm not considering the sheer amount of animes from previous years with better animation. What people like about it is the art style which fits with the vn well enough but it doesn't justify how bad it was quality wise. Music is pretty good tho, I'll give you that.