What does the software or service do well? Buzzstream does a fantastic job providing marketers and in particular, marketers that work with SEO, a way to set up templates for email outreach, evaluate websites for outreach, save potential outreach partners to a project, and then quickly send pre-created emails to those websites. Buzzstream will help you find contact info and speed up your workflow for outreach and link building! (Plus they are very reasonably priced and have pretty much the safe features as higher priced software!
What does the software or service not do well? I think the UI would be cleaned up a bit and some of the features are buried. (Once you have created a template or found the feature you are looking for, you will have no issues, but it might take you longer than you feel it should.)
What do you wish you had known about the software or service before using? Really nothing. They provide a great trial and there is no reason not to take advantage of that before signing up!