Good: 

Easy to use, working with Adobe Illustrator is swift and straight forward as it can get, expectable from one of the leading Design Software developers. Many file formats are available and support is enough through online resources and FAQ's.

Bad: 

If you are on a budget you might be in trouble with Adobe Illustrator. However you can rent it through Creative Clound if you MUST use it. Application needs a powerful computer to use it efficiently.

Bottom line:

Adobe Illustrator is the top of the line software for amateurs and professionals. It's solid operation gives you a fast workflow and it's tools can help you achieve any project never minding it's complexity. A license is steep at $600 but you can rent it through Creative Cloud.