It's tough to say he is the best when he lost to Jake Shields in his first fight. It is also really hard to judge guys in different weight classes. I think he could become the LHW champion in strikeforce soon. I think he can beat Mousassi, King Mo, or Feijao on any given night. I can also see him losing to Mousassi or Feijao as well.
Mousasi outclassed Dan in sparring , he would rip him a new one in a real fight .