edleo2002, I have both Beginner to Winner and Guy Cribbs Gybing and Core skills. Both are great, well worth the purchase. Guy Cribbs DVD is focused more on Gybing and is very easy to understand. Jem Hall's Beginner to Winner covers a lot more eg. from beginner to a intermediate level, including gybing, tacking, waters starts, beach starts, gear, etc, etc. Personally I prefer Guy's DVD probably because it covers Core skills in more detail along with gybing itself, including light wind gybing, and advanced Gybing, as well as muscle memory training etc. It's quite a detailed DVD, yet easy to follow.
I can't imagine you'd regret buying either. One covers a broader range of topics while one is focused more on Gybing and Core skills.
Hope that helps.
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