I went to Classic Jewel with two friends to grab a cocktail and I have to say that this place is definitely below average compared to what you could easily find anywhere in Las Vegas, particularly with the Strip and downtown being so close.
This place is located basically in between the strip and downtown, which means that there are plenty of other bars/restaurants in the area. Classic Jewel is very small, but also doesn't get very busy which means that it will not get crowded in there.
We tried the twisted old fashioned, the heat, and the Royale Flush and they all tasted good, without being exceptional. For that price, you can easily get very similar drinks anywhere in Las Vegas.
In conclusion, I would say that this is an ok place for a quick cocktail but that it is definitely below average on the Las Vegas scene. Feel free to message me for any additional details that you may need!