I went ahead and installed mCOLe on my desktop today and opted to set up Systemd-Boot since it works well on my laptop, and is a nice light UEFI bootloader. Thus gives an option to use systemd-boot instead of GRUB which requires the ESP to be on /boot rather than on /boot/efi how GRUB wants it. Everything works fine until updating though, where it installs GRUB and tries to replace systemd-boot. Upon doing so GRUB will not work, it could have probably been fixed via chroot, but since I wanted systemd-boot I deleted it from my ESP. At this point things would have been fine if my BIOS allowed me to select a custom .efi entry since the systemd-boot one was removed. It's not a big deal for me, I just re-installed and opted to stick with GRUB (it'll let me boot things on other hard drives anyway) but I thought I would mention that a straight update will not respect your installation options if you pick systemd-boot. I would suggest adding either a warning somewhere saying it won't work, or some sort of fix, though this could be an issue on Manjaro's side (I haven't tried it there). Anyway, just thought I'd share that experience. I suspect uninstalling GRUB before an update would have fixed it, though I'm not sure why GRUB was installed to begin with since I was using systemd-boot.