IMHO, Arch Linux is only good for those with very shallow technical inclinations. For all of my significantly technical use cases, Arch felt like a sham to me.
Off the top of my head, here are some of the things that drove me crazy about Arch.
Up until very recently, Arch Linux had no proper "multilib" support. This meant that in order to compile 32-bit packages on my 64-bit host, I had to recompile GCC. There was a package for this with AUR, but it broke regularly and had to be recompiled, sometimes with patches applied by hand, and with other hacks. This is a problem for me because I like to run a custom Wine, which has only a (useful) 32-bit version. Very recently, the Arch devs put out an official "multilib" repository, which brings them up to par with every other distro I've used. Maybe now their 64-bit updates will stop being days or weeks behind their 32-bit updates.
Speaking of AUR: it sucks. For the uninitiated, the Arch User Repository is an unofficial, source-only repository of supplementary Arch packages. Cool, right? Except that the official package manager (pacman) can't access AUR. Instead, users choose from a set of independent pacman wrapper scripts which download the source packages from AUR, build them, and call pacman to install the newly-built packages. Cool, right? Except that what is by far the most common of the wrapper scripts (yaourt) has been basically unmaintained for years. To top it off, these wrappers are always slow at grabbing AUR packages, because standard procedure is apparently to re-index/re-cache the repository every time its searched. Okay, okay... but these are all *extra* packages anyway, so quit fussing! Except that many, many packages which are available for other distros are only available to Arch users through AUR. As salt in the wound, many AUR packages are "built" by downloading DEB and RPM files, extracting the binaries, moving them, and relinking them. The pattern is vaguely prevalent throughout AUR, but there's no definite procedure for doing this. It's just up to the package's "build" script.
AUR aside, the official package manager, pacman, is pretty unimpressive itself. It doesn't use an indexed cache for fast searching (one AUR/pacman wrapper called tupac does, but pacman doesn't know anything about the tupac cache, so you have to use tupac exclusively for it to help you). It doesn't have a feature for removing obsolete packages, but there are a few different sort-of solutions on the wiki that use existing pacman features and bash hackery to emulate the functionality of things like aptitude or apt-get autoremove. Get this: you can't replace one package with another that "provides" it from a local package on the command line, even though you can with packages installed from an external repository. This applies regardless of the package file itself! In the case of replacing/superseding old packages with others (like forks, compatibility layers, or wrappers), Arch Linux will refuse to install if ANY of the files in the package exist on the system. Standard behavior, but often, the "conflicting file" is a symbolic link used to choose between two versions of a library (eg. the NVIDIA GL.so vs the MESA GL.so), or a sample config file (eg. /etc/samba/smb.conf.example).
Some more minor gripes:
-More than a few official Arch Linux packages install things to /opt and /usr/local for no reason apparent to me.
-Despite Arch's "minimalist" philosophy, their packages are generally less granular than those of a "bloated" distro like Ubuntu. Google "KDEMOD" for a historical, infamous example of this
I already know how to make my own Debian packages; Arch's simple binary package system's offer of easy recompilation means little to me. I've also spent some time with Gentoo, which made AUR seem like a cheap, ugly ripoff. Even with custom-built versions of the standard packages, I found myself disappointed with Arch's ripoff of revdep-rebuild for finding and packages that needed recompiling afterwards. Arch doesn't even offer me anything unique by "combining" the source-based and binary elements; Sabayon Linux does a much better job of it by drawing on the entirety of Gentoo in the place of AUR. Calling AUR "gigantic" in front of someone who's used Gentoo is laughable, especially considering that Gentoo's packages are signed and maintained officially. And you can be _damn_ sure that those packages won't be some kid's weekend experiment with wget and alien.
Arch Linux isn't totally horrible, and it has a decent community. But if you expect a wide range of official packages, or the robustness of apt or yum, it feels like a dirty trick when you test Arch's promise of customization and experimentation. As a highly technical user, I'm much happier on (K)ubuntu, despite the stereotypes regarding both distros.