It's the most UNIX-like Linux you've seen. Almost everything is done by command-promt, which makes it run faster compared to X Windows orientated distro's (Red Hat Linux, Mandrake Linux, Lycoris Desktop/LX etc.) in theory, and runs well on older computers.
If you are new to Linux, I suggest you don't try Slackware. It's recommended that you learn most common GNU/UNIX commands before booting Slackware.
For advanced Linux users, Slackware is easiyer for them compared to X Windows orientated distro's.