The ease of use, how quickly it integrates into my email workflow (with no configuration required), its robustness for our large organization with thousands upon thousand files that need to be sent in bulk every day or week; I could go forever here! There is nothing about this program we dislike at all - but perhaps if there was an option where you don't have access/control over who can view your file before sending? This would solve some privacy issues when sharing personal documents within teams internally as well externally across multiple clients / companies etc..