Both my daughter and my son have been studying piano with Vinh since they were respectively in first grade (my daughter is now in eighth grade and my son in fourth).  They both adore Vinh.  He is clear in his technical explanations and he makes music fun.  From very early on he played duets with the kids, allowing them to celebrate and appreciate their growing skills.  Vinh is a patient and flexible teacher - he adapts to the kids' different learning styles and recommends different books and pieces that suit their individual needs and interests.  Vinh has also proactively arranged for various testing and performance opportunities for the kids (without overpressuring them to participate :)).  In short, we highly recommend Vinh!