I've used Tix 4 Tonight on multiple occasions. It is a great way to get cheaper show tickets, buffets and other experiences. As a local there are other ways to get cheap tickets or deals, but for those things that don't offer local discounts, Tix 4 Tonight is one of the best deals around.
We always recommend the many locations to our out of town guests and our family, and everyone has been pretty happy with their experience. They have multiple convenient locations, and the staff is usually pretty friendly.
I would suggest going right as they open as some of the more high demand show tickets go quickly.
In the past year we've received substantial discounts on both Penn & Teller and the Rat Pack is Back from Tix 4 Tonight and both made my pocket book very happy.