Simple to use, has great support for SEO features like keyword insertion etc., allows you full control of your website without technical knowledge or writing complex code yourself - what more could I ask? Maybe some additional plugins would make it even better! Some things are still missing but they might be added soonish (ease of publishing blog posts online).
It's easy enough that anyone can create their first site with just about no coding experience required at all; plus there are free tutorials available in many languages too so getting up and running shouldn't take very long either way. We run several websites using this software which we publish ourselves as well as other sites owned by us through our own CMS built around extracms.