The best thing about this web application is that it has an inbuilt API which makes integration with third party apps like Salesforce very easy.The only downside I can think of is I have not encountered any major issue or glitches while using secure 24 as my email hosting service. As long as you keep your security settings high than normal then there should be no issues at all! We were able to integrate our secure 24 app seamlessly with salesforce by creating custom fields. This made data entry easier because we did not need multiple tabs to enter information into different accounts. Also, having it integrated allowed us to easily track and monitor customer activity from one place instead of separate emails/apps.