The best thing about contactdb, apart from its price which i think it's very good compared to other companies which offer similar products at higher prices with less features or better customer support.
Nothing really bad but I would like more customisation options for my account dashboard as well as some extra fields (i guess it could be considered as minor). If you are looking into any sort of lead generation service then this one should definitely give your business high chance of success! We've been using their product since 2015 so far till now we haven't noticed anything negative yet. They have helped us boost our sales considerably by generating leads through various means - social media ads etc.