The best part of using contaotm for my website was that it allows me to create different types of pages, from blog posts to articles with images or videos as well! It's also very easy to use since I'm not familiar at all in HTML coding (I've only used Wordpress) so this helped ease some work load off by providing templates which are already made.
Nothing really bad about this CMS but maybe if you're looking into something more powerful then try other options out there like word press etc because they have much better support when compared to contatoTM. We were able to manage our online store easily through its interface without having any technical knowledge required.