Quote Originally Posted by untarnished View Post
I reinstalled OpenSUSE, this time mounting the Windows-created ESP as /boot/efi, without formatting the partition. Can you allow me a follow-up question? What exactly is the advantage of having a single EFI boot partition that handles both Windows and OpenSUSE, compared to having separate EFI boot partitions?
There is no advantage. You can create another ESP for openSUSE if you like. It might make the installation a little bit more complicated, but not much, I guess.

Quote Originally Posted by untarnished View Post
I just didn't see a difference. In both cases, I select the OS I want to load through the UEFI Boot menu (I have to press F12 on my laptop to get there though), and not through the "other menu" (the menu that allows me to select "Advanced options for openSUSE"...which I guess is the GRUB2 menu?). Windows 7 and OpenSUSE 12.2 both load fine whether or not I choose to use a single ESP.
You can select either openSUSE or Windows in Grub menu (once you have added the correct boot entry for Windows) whether the boot loaders are in the same ESP or in a different one (or similarly in another ESP on another hard drive). You should not need to use the UEFI boot manager. Of course you can do that too.