Concrete5 is best used when the site has a marketing oriented strategy. It can also be effectively used to host school sites, business information sites, news, sport sites etc. Its excellent to host a personal website which is not just a blog but something more as well.
Concrete5 is best comparable to WordPress in terms of level of abstraction offered and provides an edge with the drag and drop feature. It is more responsive that a few other CMS’s and definitely provides unique and useful features.