Ranked in these QuestionsQuestion Ranking
Pro Excellent documentation
Arch's goal of simplicity means there's usually one preferred way to get things done - through organized and well documented configuration files. This focus, combined with the community's recognition that configuration files can be intimidating, has resulted in excellent documentation that's accessible to newcomers, and very instructive about how Linux actually works. The documentation is often so thorough that, when searching for solutions to problems while using other distributions, such as with video card drivers, oftentimes you'll find the most effective solution in the Arch Linux wiki or on the forums.
Pro Cutting edge rolling release
Arch Linux follows a rolling release model which allows users to stay on the bleeding edge of both the operating system and software they are using.
Pro Simplicity is absolutely the principal objective behind Arch development
The design approach of the development team focuses on elegance, code correctness, minimalism, and simplicity, and expects the user to be willing to make some effort to understand the system's operation.
Pro No restrictive handholding, pure control over everything
Arch is mainly aimed at experienced Linux users, there is no hand-holding and not much in a way of UI elements when trying to install or tweak settings.
Pro A package for almost everything
If you need to install something, chances are someone in the Arch community has already made a package for it. This makes it incredibly easy for you to install and maintain all of the non-media content on your computer.
Pro As slim or copious as you want it
Arch keeps its core repositories slim and free of unnecessary dependencies. At first installation only a bare system is set up. You can easily get the other applications through the package manager. The repositories are nearly as full as those of Ubuntu, while they are often more up to date. That way you don't have to waste time with software you don't need or want.
Pro Fast and simple package management
pacman works much faster than apt-get or yum due to better mirrors than other distributions tend to select by default. There are fewer default repositories to download from though all package management is combined into one tool instead of being split into dpkg, apt-get, and apt-cache like on Debian distros.
Pro Support for a large variety of hardware
From latest wacom pads to obscure wireless cards in laptops Arch's hw support has been and continues to be good. It has worked on laptops where other leading distro's like debian/ mint/ ubuntu failed to detect and work with all hardware.
Pro Excellent package managment with the AUR
The AUR is a repository with a very extensive catalogue of build/install scripts that are contributed by users. While these scripts are inherently less secure than conventional packages maintained by a distro's authors, it's still way easier to verify the security of install scripts than it would be to write them yourself.
Con Documentation only makes sense if you know how to adjust it
While the documentation is a very valuable reference for experts, the recipes often don't actually work on your own computer. Some articles are outdated, incomplete, contradictory or duplicated. Only if you are expert enough to know which steps to skip, to adjust or which other documentation parts to plug in, you can make it work.
Con Manual install process
The installation process for Arch Linux is not as streamlined as it is in other distributions. You have to install the OS, Desktop Environment, Network software and configure everything by yourself.
Con Not for the faint of heart
Arch only holds your hand a little bit of the way. While documentation is great, you are expected to know what you're doing. The result is that when you find the solution for a problem on a forum or elsewhere, the response may be completely over your head. If you're not well-versed in Linux, what would be a minor issue on another distribution can become a drawn-out research project on Arch, as you learn all the inner workings of the operating system, until you understand it well enough to solve your problems yourself.
Con Fragile package manager
Updating an Arch system is always a gamble. The problem could be as simple as a package having a bug causing a program to crash on start or it may be something bigger like the WiFi or Bluetooth no longer working. There is also the slight chance the system may not even boot at all after a large update.
If the user does not plan to read the forums weekly/daily or update fairly often, things can go wrong very fast.
Con Too many package upgrades that require manual intervention
Every year or so there is a update to ArchLinux that will break your system unless you first read the front page of archlinux.org. This happened with SystemD and with a few other updates that require you to do prior steps befor pacman -Syu.
Con Requires expert Linux and command-line knowledge to setup
Going in with zero Linux knowledge is not really recommended when wanting to install Arch, though it can be a good learning experience for those that are dedicated to trial and error as well as reading many faqs.
Con Rolling release requires bandwidth
Arch uses a rolling release model for updates. Unlike, for example Ubuntu where a new version is released every six months, packages are updated when they are ready. The advantage is a very up to date system and that the work of upgrading can be spread over a longer span of time to a point where it is hardly noticeably effort. However it can be difficult for people without a high bandwidth connection, or with limits on how many GB can be downloaded imposed by their internet service providers. A GB a month of downloads is quite possible.
This can be somewhat offset by Arch being lightweight, besides the relatively small core, the user selects what is installed (and has to be updated).