When comparing Blogger vs Grav, the Slant community recommends Grav for most people. In the question“What are the best blogging platforms?” Grav is ranked 8th while Blogger is ranked 17th. The most important reason people chose Grav is:
Well designed, easily usable and modern admin panel is a boost as it lets Clients edit the content easily.
Specs
Question Ranking
Pros
Pro No ads
You can turn on ads if you want, but you can also keep your Blogger blog ad-free. That is different from WordPress.com (free hosted WordPress) where there are ads, and you cannot do anything about it.
Pro Every Google account has one
If you have a Google account from any other of their services, such as Gmail, Youtube or Google+, you automatically have a Blogger account as well.
Pro Supports multiple authors
Multiple people can contribute to a single blog.
Pro Custom domain support
You can use either your own URL or a *.blogspot.com URL.
Pro Free
hosted by google
Pro API
The Blogger API allows you to publish and manage your content via a custom client app
Pro Allows custom advertisements
Such as project wonderful, or just google adsense,. so you can make money from your blog.
Pro Javascript friendly
You can include Javascript snippets and widgets (like Pinterest widgets for example) in posts and in sidebar items. This makes it very different from WordPress.com (free hosted WordPress) which does not allow javascript plugins.
Pro Android and iOS mobile apps
Allows viewing and editing content from your mobile device.
Pro Analytics integration
There's very basic analytics, but you can upgrade if needed.
Pro Easy to use admin panel
Well designed, easily usable and modern admin panel is a boost as it lets Clients edit the content easily.
Pro Easy creation of templates and content
Supports Twig for templating with Parsedown for fast Markdown and Markdown Extra support.
Pro Built-in package manager
Pro Custom fields for content
YAML-based page headers allow you easily add custom dynamic fields to your content.
Pro Open-source and free
Cons
Con Bad post editor
It is a WYSIWYG html editor, and it would be a bit better if it used <p> tags. Instead it uses divs and brs everywhere, which leads to inconsistent or just crappy typography and spacing.
Con Limited authorization system
Sadly the authorization system is fairly limited. Co authors can post and publish, without you getting a chance to pre-check their posts as an admin. e.g. you can't give them "create" and not give them "publish" permissions. They can only edit their own posts however.
Con Can be very slow
Loading times can be huge - results may vary on your use of template, but even a fairly lightweight template can load quite slow.
Con Not fully HTML4 or 5 compliant
And impossible to get it perfectly accepted by the W3C verifier no matter how much you tinker.