"generally knowing where stuff is" has been my favorite part of using Arch. I started out on redhat systems back in the day, and kinda figured out where the really important stuff was, but never wrapped my head around everything. Adding things piece by piece as I need them to Arch is much more instructive.

Indeed. Arch is an education on the Linux software stack.

IMO boot time isn't a big selling point anymore with SSDs in the market (albeit not exactly affordable). A MacBook Air can boot up within seconds and that's plenty fast for me.

I guess that's slightly less expensive than just getting a crazy fast SSD drive.

Not if you factor in the time investments.