Henneseys is an okay place. Nothing particularly special about it. It's fairly over priced for the quality of food that they have, but then again everything on Freemont street is. The only time I go there to eat is on Tuesday when they have a 2 for 1 breakfast and burger special. The burgers are nothing great, so I usually opt for the breakfast instead. Their breakfast entrees have a bigger portion, which mean more left over and are more filling.
The service is decent but nothing amazing. They used to have trivia night, but that got discontinued. If you are on Fremont and want to visit, I say go on Tuesday.