Mailgunner here. One of the things that differentiates Mailgun is that we don't gate features, all our features are available for all customers. We've found that a lot of customers don't have a lot of volume (say only 5000 emails per month) but the want inbound email parsing, email validation, complete tracking and analytics, and detailed logs through our events API. You can do all this, even on our free plan with 10,000 emails per month. So, its really what you value at what price. Hope that helps.