Great game, moves fast and you need to be thinking ahead to plan your strategy. The expansions are great too.
We bought a number of games (different styles and number is players) but Splendor has been the one my wife and I have played the most.
Great game, lots of strategy and tactics but also very simple to teach and play. Highly recommend. I can only imagine it gets better as you wrap your head around it more, and increasing the player count would certainly add to the tension and uncertainty of other people's turns.