I personally view Arch as a "poor man's Gentoo." It's a rolling release, which is great considering the never-finished state of free software. Many projects have different release schedules, which means that stable distributions will always miss out on the newest version of X% of their packages. With Arch, those updates get pushed when they're ready, instead of pushing what works by the release deadline.

Arch also has the AUR (Arch User's Repository) which provides a lot of software that isn't available through most distributions for various reasons, such as quality, stability, maturity, patent, freedom or packaging/dependency issues. This makes customization a lot easier, at the expense of all the trust, stability, and security expected from using a distribution (I guarantee none of you actually verify the packages aren't malware when installing through AUR)

From my perspective, Arch seems a little expedient. It provides a good Desktop experience, but is not as robust as distributions based on package managers like Portage, APT, or RPM. It is a lot easier to install and set up than Gentoo though, and provides similar benefits in terms of software freshness and builds with a few different configurations - hence my assessment.