What does the company do well? When you receive your reports on various email campaigns, they supply plenty of information for your records.
Also, they have a fantastically generous freemium plan so you can try out Mailchimp before you step up to their premium service.
What does the company not do well? The biggest disappointment is automation by far. While the auto-responders are great, but you do have to monitor your campaigns rather vigorously to achieve optimal results.
What about the company do you wish you had known before purchasing? While the company's core product is one of the best in the market, I wish I would have researched alternatives before-hand. There are many products that will satisfy small businesses with small audiences.