I would say put it on whichever makes you feel more comfortable. If this is a personal single-user PC, it really does not matter at all as long as your ESP is of decent size.
Which is better is subjective and depends on what you are doing. The most common reason to put it on /efi is if you have multiple operating systems, specifically multiple linux images that might have the same name. They tend to get installed to /boot so if you have multiple arch linux distributions, and your ESP sits on /boot, then your multiple distros will have the same /boot and will probably clobber each others' files. The other reason is if you have settings that keep a history of recent kernel images in /boot in case of a failed kernel upgrade. Storing them could take space. The installation wiki maybe should have a note mentioning that there are advantages and disadvantages to /efi vs /boot, but it's inconsequential for most users and probably a distraction for newcomers. As for the spec, their recommendations are just... recommendations. I'd probably follow them if I was configuring a data center, or more likely developing software for one, but for normal users, autofs is more pain than it's worth and I'm not sure I've ever heard of someone complaining of their ESP vfat integrity failing for being mounted too much (it needs to be mounted for kernel upgrades anyway). I have my ESP on /efi and /boot/efi. I've found this to be the best combo of working with old tools that use /boot/efi, newer tools that expect /efi, and multi-os systems that use the same 'initramfs-linux.img' and 'vmlinuz-linux' naming under /boot. As an example, the mkinitcpio defaults for UKIs use /efi paths which saved me maybe a few seconds of typing. tl;dr: If you have more than one operating system, choose /efi, otherwise it probably does not matter. -Scott
