I have only been to 2 conventions, one small Creation con and a large Creation con in Las Vegas.
I have to say that Jonathan Frakes was a total surprise for me. He was so engaging, funny and warm that I was almost blown away. He left the stage to be closer to people in the Q & A session, and he went to the back of the (very large) hall because "people in the back want to take pictures too!". I had never really given him a second thought before, but now I am a fan!
Jeffrey Combs is highly entertaining when he is on stage (especially at the smaller convention where he had more stage time. He and Casey Biggs did a session together and it was almost like watching a comedy duo). He was also very engaging when I got his autograph. I thought I'd have no trouble talking to him, but when I got in front of him I realized that I really had nothing to say! I have to give him credit for carrying the entire conversation when he could have just signed my dvd and moved on to the next person.
Ah yes, Frakes is a wonderfully entertaining guy.
I didn't know who Jeffry Combs was at first, though the name did sound familiar. So I had to google him, and holey cow! He played Brunt, Weyoun, and that blue Andorian guy on Enterprise! I can't believe they were all played by him!
In my opinion that makes him a very talented actor. Many actors have great charisma and presence, but they are a one trick pony, they act the same in every roll you give them, But this guy can really put on a different act each time he plays a role.
I just spent like 2 hours youtube-ing him, watching a lot of little interviews.