Campaigner

The interface is very user friendly allowing for drag and drop editiong or html editor features make Campaigner a breeze to work with. In addition, being able to automate an email to go out weekly, or every two weeks, three weeks or four weeks is a great feature.

Sometimes Campaigner is caps sensitive with linked documents, which will sever links if you're not careful and unless you pull it into html editor you may not be able to see the severed link in the drag and drop editor to apply changes.

We use it for simple email blasts to our neighborhood association. We don't use it for marketing campaigns, so therefore do not have the need for some of the functionality available with Campaigner. For our needs it works.

Ease of use. It is not intuitive, and they haven't done any kind of software or GUI redesign since we started using it (6+ years ago).
Making a template should be a lot easier than it is: Creating and editing templates has a lot of old graphic (frames?) technology that makes for a frustrating experience when trying to line up text blocks with headers, footers and images.
Writing an email with attachments should be easier. Having to upload a file/image to the media library, and then importing it into your email is a lot of steps. Instead, allow a person to add a file/image to an email note in the same simple fashion as any other email client works: add a paper clip button and allow us to select the file to add to the note. That seems like it should have been done a long time ago.
Also, if you accidentally remove a person from an email list, you have to call up Campaigner support to get it fixed; you can't manually fix it yourself. Very annoying.

easy to use.
Cover most function that we need.
Drag and drop save a lot of time.

RWD.
UI of administer.
The report after importing contacts is terrible. There is only the row number on the report and then i have to check the original mailing list to find the email myself.
Sales is difficult to find and inefficient.