The 4 stars are for the Tequila bar. Located in Treasure Island, Isla has HH everyday from 4-7 PM and offers discounted prices on beer and cocktails. Also, the bartenders are extremely helpful and even let you sample different tequilas that they personally recommend.
They have a HUGE tequila menu but I would chat with the bartenders, specifically Teri, and ask for recommendations. Do you really want to sit at the bar and read a 30 page book? Depending on your price range and taste, they can suggest one to your potential liking.
You can either sit at the bar or on one of the small couches adjacent to the casino.
The restaurant food is another story. I would solely come here for HH or the Tequila bar. Their guacamole is extremely fresh and full of flavor but that's about it. The tacos were sub par, especially for Vegas. I really regret not trying Roberto's Taco Shop, which our taxi driver complimented.
If you like tequila that has a soft caramel finish, try Frida Kahlo.