In the interest of parity, and since there have been a lot of Debian-only posts in the past, here’s reflector — an Arch-only trick.
Mirror management is usually an easy-to-forget, one-time task when building a system, but it might be worth keeping reflector in mind.
I’ve used rankmirrors plenty of times, and if there’s no other available option, it does a fine job. But rankmirrors does expect you to do a little background work, and at times can be a bit time-consuming. All of which is easy to work around, of course.
reflector, in my humble opinion, has the added bonus of being able to filter mirrors by geographical area, which is great if you’re a world traveler and want to update between stopovers.
Or it might just be that some of the mirrors rankmirrors gave you are sluggish or remote, in which case reflector might have a few better ideas for you.