"Best" requires some context. Its like "big", it doesn't mean much without the context its in. Some of the factors to consider:
- Who is managing the content, and what is their skill level.
- How many people need to authenticate, for managing content, and/or accessing protected content. Do we need permission levels (ie a full blown admin and then someone is allowed only to write content ... should they also have publish permissions?).
- How often does content typically change? An occasional page change is different than a site with an active events feed, active blog (maybe with comments, etc), promotions?
- The skill level of the person managing the site (ie the code and hosting environment)
- Features. This is a big one. If we are talking "basic page" type content, that can be handled by every CMS ever invented. Where it gets dicey, is building out potential CMS features from there ... ie blogs, selling something (ecommerce), news feed, event calendars, image sliders, RSS feed, caching, contact form, image management for galleries, SEO management features for meta tags and Open Graph, etc and on and on. As some code-challenged individuals have mentioned, you could write all this from scratch. But why? Just take writing a CMS based event calendar. Think of recurring events. Look at how Google calendar does that. How many hours to come close to that funcionality (probably in the 100's of hours of programming time to re-invent a f'n wheel).
- Documentation and support
Assuming there is an important client relationship here, the worst thing you could do is write this yourself. a) it will very unfeatureful b) it will be really difficult to extend or add features to and c) if you get hit by a bus many people will likely be cursing your one-off POS.
That said, I've done tons and tons of WordPress and Drupal. I've dabbled in Joomla and Expression engine. I've evaluated concrete5 and several others on behalf of clients. My opinions:
- Anyone that claims php is inherently insecure is either living way, way back in the past, or just regurgitating something they read on the internet and wasting their breadth and your time.
- I have never seen a good reason to use Joomla over the others. Ditto Expression Engine.
- WordPress has hands down the best management user interface. It is less painful for clients to learn.
- WordPress has the best support / documentation in their overall ecosystem (ie official and otherwise). Want to do something you've never done before? WP is a good choice.
- WordPress has the best third party integration tools.
- WordPress plugins can be great, or really awful. Be very discriminating, and that can be a big plus (but very much a double edged sword here).
- WordPress tends to be easy to upgrade. There is a lot of effort put into making that really simple and very backward compatibility.
- WordPress started as a blog builder, and is hands down the best blogging platform out there.
- WP has really good responsive image handling built in (using srcset).
- WordPress (core) is probably the most secure CMS out there, despite the perception of the uninformed who are being swayed by click-bait blog headlines. It is the most scrutinized. Its is also the most targeted because of its popularity. Be wary of any plugin. Keep a secure server environment, and if you don't want to do routine updates, then do what you can to harden the system. (I manage a bunch of WP sites for clients. I have one that is running WP 2.6, which probably dates to 2009, and its not been touched by anything malicious because its hardened to the bone).
- Drupal can do more "site building" type stuff from within the CMS. To get comparable from WordPress, you need to write code or use plugins (boo). Things like blocks, views, content types and taxonomies, and triggers, can be powerful tools to build and manage a site. Views is particularly powerful, but the learning curve really, really steep.
- Drupal has better built in user management tools and features.
- Drupal has better tools for doing stuff at a web service or API level, eg a decoupled CMS or supplying content for an app (WP is catching up).
- Drupal has a built in feed aggregator.
- Learning curve is steeper here for coders and content managers alike
- Documentation tends toward the anemic, or frustratingly just hard to find what you need when you need.
- Upgrading across major versions is a nightmare. In fact, you likely just need to start over.
- Drupal is a hacker target too, but not as much. And it doesn't make the blog headlines, like WP when there is something.