The Never-Ending Quest to Find the Perfect Email Service Provider
Most ESPs include basic reporting — deliverability, clickthrough, bounce and open information. Consider your requirements for email reporting, report formats and integration with your web analytics provider when evaluating if an ESP's reporting functionality will meet your needs.
Contrary to what some people think, sending email isn't free. Although it's still the most cost-effective marketing channel online, email costs money. Adding bells and whistles costs even more. Do a full assessment of your needs and how much volume you intend to send to get a realistic view of what your program should cost and what extra services you'll use. Working with a consultant who can help you determine integration points and where extra money up front will save or make you money in the long run can be worth the initial cost as well.
All ESPs claim to have excellent customer service; you won't know the truth until after contracts are signed and you're stuck with a question you can't find the answer to. Do some investigation by contacting current customers and a few user groups to find out how responsive customer service is after the onboarding process is over. Also, push for an increased level of customer service during contract negotiations.
There's no standard ESP user interface (UI) and some companies are more intuitive than others. Often companies select an ESP based on what the email marketing manager has used before. Sometimes when everything else is equal, this can be a good enough reason. However, you need to weigh functionality and other factors. If a tough UI will make it harder and take more time to send email, that may be a big enough reason to eliminate an ESP from consideration. Just be sure to fully consider the learning curve versus actual usability.