I like how easy it was for me as an administrator of my domain (a large organization)to get this set up with our existing users from other companies in various states across US time zones! It took some research but we were able solve all issues that arose during initial setup phase - including DNS changes required by SPF/DKIM policies etc., which are not always included out-of box when you purchase these products or have little experience configuring them yourself so be prepared!! Also had several requests via support tickets about configuration needed within their apps after they deployed at customers site since there isn't much documentation available online yet regarding best practices once its fully configured properly. We've been using Mailsync now almost 2 years without any major problems nor downtime incidents thus far though still early days into full deployment process; however would definitely consider adding more features such DLP / AntiVirus integration capabilities if those.