We use Joomla as an AMS system. The good news is it's free and highly customizable. The bad news is, it can be quite costly to pay someone to customize it for you. Also it is community-supported, so there's no hotline you can call! We use it for member data, we track participation/ purchases (although do not have any money in it- crazy I know!) and 2 pretty robust member directories. Its fine for a free website, but for an AMS I definitely do not recommend.