We were aware that high season for kitesurfing is from Nov until March though we hoped for some good wind conditions in May. We were not lucky and hence spent three days in Mui Ne. In general, the kiteboarding conditions are quite challenging for beginners as wind is onshore and the water is rather deep. Hence, if one's not able going upwind right from the beginning multiple lessons might be required which can be quite expensive.
The city of Mui Ne was mostly quiet and besides the beach and food and drinks at night Mui Ne does not offer a lot. If you can choose we definitely recommend to skip Mui Ne and spend more time in other places such as Hoi An. The sea and beaches are much nicer with less waste and in the afternoon and evening the pretty city provides various things to do.