The customer database is one of the more flexible ever seen, from the one-field database (email address only) to the most complete.
It's flat, mailers are not CRMs.
Maintining it, importing and exporting it's a piece of cake - even if all can be always enhanced.
Searching is fast.
Editing a customer record has been recently improved, and now it's simple to keep the history of subscriptions and unsubscriptions.
The email text/image editing is full of options and very simple to use. Everyone can get super results with little knowledge.
Never broke a session in more than 2 years I use it.
The validation procedure changes often, even if it now make sense.
It's free for small database use (up to 1,000 users), great for non-profit, startuppers and personal use.
The pricing plan is very honest and simple.
I use it for all the consultancies I'm involved in, and for small personal projects.
It's very effeicient in getting the uesrs answer, disabling automatically the bounces. A must !