Arch is a wonderful distro. For users, the main difference between Arch and Debian/Fedora is that Arch is a
rolling distro. Basically there are no versions. You're more or less encouraged to keep your packages to the newest version. The iso images they release are usually a snapshot of the repos at a certain moment in time, and not a labeled version you can get support for.
The distro may be a rolling release one, it's still very robust and upgrades break rarely. If you're familiar with
Debian's unstable branch Sid, then you know what Arch feels like.
Another major difference is the way the system behaves at boot time. Debian relies on the old sysV init system, where Arch has moved to the newer
systemd. The sysV init scripts are the ones in
/etc/init.d. If you've ever done something like that on Ubuntu:
$ sudo /etc/init.d/mysql restart
It won't work in Arch.
systemd is a new (as in "just a few years old") project which aims at replacing the 30 year old idea of the sysV init. I only took a quick look at it, and it certainly seems more thorough. But I'm a little reluctant to change something that works simply because "it's old". systemd developers claim that they can reach incredible boot speeds by launching services in parallel (it's traditionally sequential. Each service waits for its predecessor to finish its launch). I've only used Arch on a Raspberry Pi, so I cannot compare it with what I know on a traditional desktop.
A small warning!
Despite what several reviews say, Arch is not more difficult than any other distro to operate. However be warned that the install process is a little more complex and tedious than what you've seen so far with Ubuntu/Debian/Mint/Fedora. Keep a secondary device with internet access next to you during the install, there's a high chance you will need it. (You can practice installing it on Virtualbox).
Arch is not for everyone
Again, Arch is a wonderful distro. However its appeal is only apparent to a very specific kind of linux users. People interested in Unix internals, generally having a good idea of how linux works, boots, mounts disks, connects to the network, starts the X server, ... If you're interested in learning more about these subjects, than installing Arch is the best thing you can do. However, if you're not interested in all this, I think you should stick with Ubuntu.
Similar distros
- Sabayon Linux: Based on Gentoo, it provides a binary package manager on top of portage (which itself is heavily inspired by what's happening in the BSD world).
- ArchBang: Inspired by Crunchbang and based on Arch, this distro presents a minimal Arch distro with openbox as a window manager. Biggest advantage: The install process is very easy, a lot easier than vanilla Arch.