I have to disagree with two of those:

Yngwie Malmsteen was cool, took the time to meet all the fans and sign stuff. And this was when he was most successful, with Joe Lynn Turner in the band.

Gene Simmons - I've met him twice, the first time with lots of fans around, he was really funny trying to repeat what people around said to eachother (in Swedish), really enjoying the attention but at the same time very friendly and not distant or arrogant at all.

One of his bandmates should have had the comment you gave Kevin DuBrow.. and that's Peter Criss. The guy refused to sign or talk to anyone outside his scheduled signing session and this was way before the reunion.