It's perfect for transactional emails. It integrates very well with your tech products. It "talks" to most CRMs. However, we won't recommend this product for bulk mail
SMTP Email Relay Solutions is a great service if you are in a field where sending out bulk information, such as monthly statements to clients, invoices, or any back-to-back emails that would normally get flagged for "spam" is required.
From my experience, Pepipost has far better pricing compared to other platforms I tested and used. Their interface is super simple to understand and allows you to set it up with ease. Their support team is on point and responds to queries faster than any of the other platforms I have used.
Office 365 does use secure non-standard ports for SMTP connectivity causing a problem with older programs. SMTP Email Delivery from Exchange solves this problem by giving the network admin full control over ports and specific program connections. While we do use both Office 365 and the SMTP Email Delivery we find that a mix is needed in order to meet all expectations for our end users. The majority of our SMTP communications, for users, go through Office 365 while the majority of our applications and servers do go through the SMTP Email Delivery service.