One thing I have noticed is that all the deals I inquire about on TravelZoo are the real thing. The offers in their Top 20 email are genuine discounts at trusted establishments and businesses. I inquired about a sailing deal they had and when I called the business directly they were easy to deal with and spoke very highly of their interactions with TravelZoo and that the deal had received a great response. When I visited the Travel Zoo office I notice they have a whole team of people checking their travel deals and ensuring these are represented accurately (they were all on the phone 'pretending' to be customers ordering the deals.
Great service and would recommend their Top 20!