I haven't seen either movie in years, so I can't really build an objective case...
I just remember thinking Thunderball was pretty awesome and that Never Say Never Again felt like a cheap knockoff to me.
Irvin Kershner did wonders with ESB, but I can't say that I care for anything else the man ever did.
And I don't have to try to make you look stupid... that big blue anime hair does it for me! :)