Not bad, but I've seen a better.
I've been to the Lighthouse Bar on many occasions to see the free shows, which I must admit are really good. Most of the barstaff and waitresses are fantastic, although if you're sitting at a table service can sometimes be very slow. Your best bet is to get a seat at the bar proper. The female bartenders are very attractive with very few exceptions, and are great at their jobs. I'm mostly a Sam Adams beer guy, so my tastes are taken care of, but I think the beer options are fairly limited. Mixed drinks, on the other hand, run the whole gamut.
I think the most fun of the Lighthouse Bar ar the occasions when the wiatstaff and/or bartenders get the chance to strut their stuff, either singing a popular song or dancing to some popular music. They seem to be hired not just for looks and bartending ability, but also for their singing and dancing talents, which is a very nice touch.
Prices are prety standard for a nightclub, so no surprises there. What kills me every time is the apparent changes to "last call" times. Sometimes it's 12:30, sometimes 12:15, sometimes 12:45. This inconsistency really burns me. Also, a friend of mine was shut off from drinks for no apparent reason on one occasion. He'd been driniking as much as I was, he was not rude or obnoxious, was not blatantly drunk, and was not bothering customers or bartenders, yet he was shut off and I was fine. Still don;t understand that one.
Overall, the Lighthouse Bar is a great place to spend a few hours watching one of the free concerts at Twin River and ogling hot women. After the show, hover, I recommend heading up to Fado, the Irish pub located on the second floor.