I would say the Fanatic Viper is a more 'progressive board' - meaning it will see you through more of the beginner/intermediate stages of windsurfing.

There are other great boards out there - we use some 180lt RRD Easyride windsurf boards which are a great stepping stone from beginner to intermediate windsurfer. At the Poole Windsurfing School we also use the RRD Evolution 158lt & 148lt boards to progress students onto learning how to get planing, use the footstraps & ultimately carve gybe. A 158lt board such as the RRD Evolution would last a lot longer before you felt it necessary to downsize again.

Making the final decision on board size all depends on how much you think you will be getting out on the water & just how fast you are progressing with your windsurfing skills!