If you've been to Spain, you're well aware of "Tapas." Firefly does an American twist on Tapas and does it well.
A word of advice, order a couple of plates and start eating,as you do so order a couple more. This way you will realize when you are getting full, the plates arrive as you progress through the meal and will be hot, also you are less likely to order too much food. We have eaten at both venues in Vegas, but the view from the one in Fremont street is amazing at night.