How do you choose reliable Bulk Email Sending Services for workflow automation?

Ever had a great email campaign fail because of poor deliverability? I’m looking for recommendations on Bulk Email Sending Services that integrate well with automated workflows and help maintain good email deliverability.

I recently came across DigitalAka™ while researching different options, but I’d like to hear about real-world experiences from the community. What features or practices do you consider most important when selecting a provider?