As noted, it's Arch based, but it has its own repos which aim for greater stability than raw Arch. Unlike Arch itself, there are gui tools for package management and updates. I haven't tested them as I quite like plain old pacman and have gotten familiar with it through using Arch and Chakra for years, but I'd imagine that they are decent based on how well everything else seems to work. Installation is fairly easy, though not as newcomer friendly as 'buntu - certainly the easiest of the Arch spin-offs aside from perhaps Chakra (Chakra's installer is certainly prettier).
Worth mentioning also is that packages from the AUR (Arch User Repository) are compatible with Manjaro, and yaourt (a nice tool for managing them) is available directly from the regular repos unlike Arch. Once that's installed, you can easily install yaourt-gui, which makes it even easier to search and install things not in the Manjaro repos.
Manjaro seems to be to Arch what Mint is to Ubuntu in some ways - easier, more polished and less buggy than the parent (not that Arch itself is bad, just hard to install - I thinks it's worlds better than Ubuntu). I highly recommend this distro for anyone that likes Xfce or maybe has always wanted to try an Arch-like distro without the painful install process. I had a really nice Xfce setup with compiz and emerald enabled and working (yes, even emerald-themes is available!) within minutes of completing the install. And no, I have nothing to do with the distro aside from using it
); and a lot of GTK2-based programs (which is normal for XFCE, of course).
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