I had heard a lot about Arch but never tried it until the other day. Holy crap! It's everything you could want in a lightweight distro!
As far as level of technical know-how, it's somewhere between Gentoo and Slackware. You don't have to build the system from the ground up and compile every single thing like Gentoo, but you use Nano to configure networks, startup daemons, all that kind of stuff. This is my favorite way of configuring my system, and Arch encourages it.
The curses-based installer is brilliant. It's the best installer for any system I have ever used, whether GUI, command-line, or curses-based. It's advanced enough to let you fine-tune your system, but simple enough to get a command-line system going in about 15 minutes (that's how long it took me first install).
Pacman is great, the repositories have most of what you could want. It works well and resolves dependencies just fine.
Overall, Arch gets my thumbs up! If there are any Arch devs here, I want to thank you!