I like that you can customize it to your needs, as well as have control over everything from what is hosted where, how often updates are made etc.
It's not very user friendly when setting up new sites or creating pages/sections of existing ones - there isn't an intuitive method in place for this. Not much else really, just make sure any customization has been done properly before going live with the website otherwise things may get messy quickly! We use hostcms because we needed something more