I loved most of this, but at some point the plot became dumb and confusing, and I honestly didn't want to read through all of XXXHolic to figure out "why is this bad guy doing this". You shouldn't have to read through multiple other works, to get what's going on in this.
I've read a lot of Clamp, but the fact they made these two so intertwined is just..bad. The multiple plot twists were just so stupid and it felt like they were trying to write something edgy, that would get attention, rather than a story that we should care about.