I've been a customer of 23andme for 3 years, and they've always been very forthright about providing guidance on what you really could discern from the results they provide, including a measure of the strength of the scientific evidence that provided probabilities of you getting this disease or that one.
Personally, the highlights for me where when my Brother, Mother, Niece and Nephew tossed their results into 23andme, and it instantly identified them as relatives, and what their relationship to me was - without any last names or locations to go on. (Though admittedly, my niece and nephew were identified as "Niece/Aunt, Nephew/Uncle)
I've been happy with the sober, reasonable, and conservative approach that 23andme has taken. "Genewatch" on the other hand, sounds like they have an axe to grind - they certainly lost credibility with me based on the comments I read. Not sure what their issue is...