The Select tier is perfect for design, delivery, forms and reports. If you're coming from another emarketing platform like Swiftpage emarketing (SPEM) or Act! emarketing (AEM), and want to continue the same type of emailing with better design & delivery tools, the "Select" tier is an easy choice.
Select is perfect for those designing business newsletters, and sending up to 10,000 emails per month with normal delivery or with some additional delivery workflow after the newsletter. What this means is you can trigger additional emails to be sent based on how the recipients respond to the first one. For instance, you can trigger a follow-up email if they open the newsletter, or resend the first one (with slight modifications) if they don't. It's a new level of emarketing interaction.
Select users can also build simple landing pages to capture basic data with webforms.
So the simplest way to understand the difference between Select and Complete is the former supports "outbound delivery workflow", and the latter support that AND "inbound response-driven" workflow. If you review the comparison chart, you'll notice that most of the differences between the first and second tier follow this theme.It should be noted that Complete also has another 40,000 sends per month (total of 50,000), and more robust Webforms & landing pages that support many more types of data fields, like checkboxes for example, that allow users to present a more meaningful survey to their audience than Select supports.
The case for Advanced is even simpler. Those that need advanced features like a/b testing or multi-stage lead profiling already know what they are, and understand the benefit of them. These are sophisticated marketing tools, and if a user is qualified to use them, they likely know their value well enough to justify the extra cost. The only other reason a user would justify the extra cost of the Advanced tier is based on the increased send limit, namely the extra 50k included with the top tier of AMA for a total monthly send of 10,000 emails. In these cases, the math will speak for itself.