Kua Mexican Kitchen is an authentic Mexican restaurant that prides itself on having traditional…read moredishes which are "truly" Mexican as opposed to the popular Tex-Mex style that dominates Mexican restaurants nowadays.
Right off the bat, I would recommend Kua mainly because of the fact that it is one of the few Mexican restaurants in The Hague, plus it is the only restaurant (that I know of) that serves traditional dishes (the rest are Tex-Mex). So if you're used to Tex-Mex, I would highly recommend to go to Kua and try the traditional style Mexican food, as it is totally worth it.
As for the service, the waiters are friendly. No negatives there. Despite my positivity about this establishment, there are some negatives. Firstly, the dishes are quite small. This is a shame because it's not advertised as a small plate/sharing type place. Secondly, the restaurant itself is also small, meaning that there isn't much space available, which leads me to my third negative point, you 100% need a reservation. Since the restaurant is small and good, it's quite popular. This means that it's always full and it'll be hard to get a table without having a reservation.
Overall, I would recommend Kua mainly because of it's authenticity and the quality of the food. It may not be the best Mexican food ever, but The Netherlands isn't known for it's Mexican cuisine, meaning that Kua is the best restaurant available.