What are the differences between Thor Vs. Thor?
Well the main difference seems to be that solo Thor is thoughtful and actually seems to think before he acts. Really it wasn't until Busiek's Avengers that Thor came across as a dolt. Read any of the Avengers titles from the 70's & 80's and Thor actually comes across as a thoughtful character who often contemplates his place in this team of mortals. Thor has always been a braggart in battle but the moment the battle is ended he usually goes back to exhibiting strong traits of humility. I never took it personal that Thor was a bit watered down in Avengers titles because even as a kid I understood this was a team book and a full powered Thor wouldn't have a whole helluva use for his teammates (perfect example is Avengers 149 vol 1 Thor fights and defeats Orca after he easily beat the whole team singlehandedly).
Busiek in turn didn't write Thor like a proud god but more like a spoiled angry child who when he didn't get his way was prone to lash out. Examples of this would be destroying a news camera man's camera with mjolnir and quitting the team when a govt. agent made changes Thor didn't approve of. Thor was screaming and shouting like a child while his teammates tried to calm him down. The problem with this is future writers seems to have taken to the watered down in intelligence Thor and this is the guy who now seems to appear anywhere outside his book.