It depends on what you're talking about. With relatively fast internet (I have 20Mb/s), I can have a functional box up with my favorite DE in just an hour or so. It's true that I configure things here and there for the next couple days as I need them, and each configuration is simple and only takes a second or two, but several hours seems a lot longer than the average install to me.
The biggest gotcha for me as a newcomer was trying to install on a laptop, having no ethernet access handy, and not knowing that I'd need to install wireless_tools when running through the initial setup in order to get online.
The amount of time it takes varies greatly according to what you consider to be complete. I never stop tweaking my system, and there are always some points of dissatisfaction with it. But Arch is a great distro. It's very well-documented, and is pretty much delightful to configure.
1) I previously tried in a virtual machine 2) I had a second machine next to mine to look up stuff in the wiki and follow the installation guide.