I just got back from Mui Ne after vacation 6 weeks Kiteboarding there.
The wind is very good, but if you want to learn there is only one shool at Sailing club hotel.
The Full Moon hotel have very good rental gear for Windsurfing ( 2003 Starboard and Yes sail) and Kiteboarding is Air rush 2003.
I Don't know Pascal the owner of Full Moon have any instructor yet.
The reason I am wondering, because when I was there from Nov 28- Jan 4/2003 I was the only Instructor allow to teach by Pascal.
Mui Ne is 14 km long sandy beach with no Coral, Sharks, funny Jelly fish.
The water temp is around 70F-80F little current is always on shore.
Wind is side on shore come from North East Oct-May and South East May-Sep.
Please check this Web site http://www.windsurf-vietnam.com
for wind speed and gallery.