Processwire certainly is a CMS for Developers, if you dont know frontend development you won't be happy with it. Period.

The thing with Processwire is that you can convert exisiting templates extremly fast to a functioning site without changing any of your HTML Markup. You simply retrieve your content whether productitem,newsarticle,static page etc from the api and echo it.

Managing content is fairly simple for the end user because mostly the site tree reflects your frontend site structure. My clients come from TYPO3 or Wordpress and they enjoy the distraction free admin interface that leaves them basically no option other than creating pages or editing content.

Also updating Processwire is super easy. You can just override the system directory with a new version and you are done.

I once created a Wordpress template and from a developer perspective I did not enjoy it. I did not like the way of splitting your template that much and found myself constantly googling for certain tricks to disable things in functions.php .

Of course Wordpress shines for a non developer. Tons of templates and plugins installable with one click to get you started fast. The admin interface also is great (ignoring the fact that static pages are still not organized in a tree) Mostly people use the install tool of their webhost and so on.

But that is not the target audience for Processwire. Processwire is good for freelance developers and agency creating sites for small to medium businesses

If i look at posts like this http://wpapprentice.com/blog/10-reasons-use-wordpress-run-business-website/ I see many reasons to use Wordpress that actually don't are dependent on the CMS but on the plugins and themes. E.g "Wordpress is great for SEO" is only valid if your theme is properly configured and you use wpSEO or Yoast.

Posts like http://www.sitepoint.com/wordpress-framework/ are simply (to this date) not true.