Round 1, FIGHT!

No, really. How would you compare these 2 popular distros? If I am going to install a Linux distro (over BSD) these 2 would probably the 2 I would consider.

Preferences?
Differences?

Thanks guys!

Well, I consider ArchLinux to be "Slackware++". Its got the compatability and simplicity of Slackware, but with amazing package management, more up to date packages, and i686 compilation.

Its also got a nice community. I find it a lot friendlier than Slackware's. Slackware users tend to me umm....religious about it.

Coming from (free?)BSD you will probably appreciate the Arch package manager pacman. You can use it to update your system and install/uninstall (binaries) with dependencies. If you prefer building from source pacman has a sibling called makepkg which you can use to easily generate customized packages. It's all pretty simple and transparent. Perhaps similar tools exist for slackware? I honestly don't know.

Slackware has a much bigger user base and has been around for a decade or so. This might count for something. While my experience with Arch (as a desktop system) has been good and solid it is still 0,5...

Slack is great... But Arch is really the better distro.
It is faster, has better package management and simple configuration.

Take Arch.
(why would anyone stop using freeBSD? I use linux because my addiction to America's Army and I have a ATI graphics card )

I'd like to agree with everyone so far - Arch is probably better of the two: the same simplicity and transparency that makes Slackware great, but Pacman is bonus for package management. There are only two reasons I can think of for chosing Slackware over Arch: one, if you want to run it on architecture other than i686. Two, if you really need any packages covered by Slackware but absent in Arch.