Feature
Easy to use
Great for blogging
Many developers and skilled service providers
Routine updates
Many existing themes (designs)
Many free custom plugins (features)
Developer friendly
Fair amount of plugins (features)
Highly customizable options
Strong community support
Well-established community of developers and users
Highly customizable architecture
Still requires some minor programming knowledge to customize
Best templates are built off “framework templates” and require design knowledge
Plugins can conflict with updates to platform
Plugin developers may abandon their free tools
Not designer friendly
Requires programming knowledge
More clicks or steps to publish updates
Not as user-friendly for updates
Less free themes or plugins
While not personally a huge fan of Squarespace, it does have a growing community of users. The main benefit offered is that Squarespace hosts your site, maintains updates, and allows site owners to easily customize the look of your own site. The downside is still less plugin (features) support without knowing programming knowledge. Again, as they maintain the content, please review their Terms of Service.