Probably the installation of the distro itself, since it doesn't have a graphical interface that most computer savvy people are used to. I've heard that nvidia driver installation used to be complicated, and it's usually necessary to employ command line for that. And even after you install Gnome or KDE, you'd still probably have to use bash for many, many things that you want to adjust or install. Oh, and since it's a rolling distro, it can easily stop working after you update it. That's what I know, I've never used Arch myself, been sticking to Debian-based distros for now.