Wasn't sure what to expect, as the place is quite small, but really glad I went. Thankfully we arrived around 6.45pm and ordered the food. I say thankfully because by the time the food was eaten the place was full. Not by by people who wanted to eat, but by those who wanted to listen to music.
As it was my first evening in Prague, having been up since 4am, I had planned to get a relatively early night's sleep in readiness for sight seeing the next day. But that all changed. I enjoyed myself so much I didn't get to bed until the early hours. Highly recommended.