Black Star would probably see Asura as a new opponent to prove his strength against. He would be eager to fight, shouting his usual boasts about being the one to defeat the most powerful foe. However, he might quickly realize that Asura is on a whole different level and would need to rely on his friends more than he thought.
I think it is. The plot has depth, the action scenes are exciting, and it has a good mix of humor and drama. However, it might not be for everyone depending on personal preferences.
The Soul Eater manga did end. It wrapped up its plotlines and gave a satisfying conclusion to the fans. However, opinions on the ending may vary among readers.