One other case of interest (and there are plenty available) is the official OEM LG Folio Case CCF-210 which retails for $50 at AT&T stores and is available elsewhere for less. The case includes an integrated back which replaces the back door of the phone and has an attached folio cover.
The good things about it are that the cover shuts off the phone's display when closed, it has an integrated NFC connector which can be used with a Qi wireless charger, and that it adds essentially no bulk to the phone.
The worst thing about the folio case is that it doesn't offer any protection to the sides or back of the phone when dropped, and not much to the screen if it's open when the phone impacts something.
Folio Case for the AT&T Optimus G Pro, (E980) | LG USA