Using iMIS has meant that our member data is fully accessible in one place for both our office team and our members. We use it for subscriptions, events, eLearning (via TopClass) and accreditation, as well as the RiSE CMS to manage our website. It's user friendly and it's great that it's cloud based as we can access from anywhere.
The main downside is that sometimes it feels like you need a whole tech team to deliver anything bespoke/different from the out of the box solutions - we're a small organisation without inhouse IT support.