For long-term email marketing, I wouldn't recommend price as the deciding factor. A provider with a high deliverability rate, reliable infrastructure, and strong regulatory compliance typically generates a much higher return on investment in the long run than a cheaper platform with poor inbox delivery.

When evaluating providers, I recommend prioritizing these factors:

Deliverability: Analyze the sender's reputation, authentication support (SPF, DKIM, DMARC), dedicated IP options, and delivery monitoring.

Compliance: Ensure the platform complies with GDPR, the CAN-SPAM Act, and other relevant privacy regulations, and includes consent management.

Automation: Choose a provider that offers customer journeys, behavioral triggers, segmentation, and personalized campaigns.

Analytics: In addition to open rates, focus on click-through rates, conversions, revenue attribution, and engagement trends.

Scalability: The platform should seamlessly handle contact list growth and integrate with your CRM, e-commerce platform, and other marketing tools.

Customer Support: Effective technical support is especially valuable when delivery or campaign issues arise.

For growing businesses, I've found that platforms like Klaviyo (especially for e-commerce), Mailchimp, Brevo, and ActiveCampaign offer advantages that vary depending on the business model and automation needs. Rather than choosing the cheapest option, I recommend selecting the provider that best fits your current marketing strategy and projected growth for the next few years, as migrating platforms later can be costly and disruptive.