Installing Arch is easy as long as you don't want to do anything clever. As soon as you want to do something like setting software RAID up, it becomes much less easy :P. At least that's been my experience.
Maybe with my next laptop I'll try Arch properly, but it was too much of a pain last time I tried to install it with my current setup.
I generally don't set up RAID on any of my machines because there really is no need. A quick google search though returns tons of stuff on the archwiki, which goes through preparation and installation/execution. This isn't only the case with RAID. As awayand said, the documentation is golden.
Maybe with my next laptop I'll try Arch properly, but it was too much of a pain last time I tried to install it with my current setup.