I've only been to Greek Bistro for lunch (several times) and have had their salads (good), spanakopita (okay), and gyros (good). The service is good and friendly.
The place is small, in a strip mall, and is not the typical restaurant atmosphere that you would expect when you are having someone wait on you for dinner. With that said, the prices are a little high for lunch and to have to tip on top of that...not for just a good salad. They should go back to more of the casual service environment they used to be where you order at the counter, get your number, and they deliver to your table.
I like them, but I've had better Greek food in Vegas for their prices.