If you are a fan of Blu-ray and the best possible presentation of the original films, then these are the way to go. I myself am nostalgic, especially for the AIP dubs (which the BRD's don't have as Jelly mentioned). So that is why I have both.
I am still awaiting a nice official DVD/BRD of Gammera The Invincible, and a version of G vs Barugon (aka War of the Monsters) with both English dubs. This is one of the reasons why I appreciate those previous *questionable* DVD releases as they presented most of the AIP versions as I would have seen them on TV in the 70's/80's. Also a version of Super Monster with Filmways opening/closing credits (I curse the day I *thought* I had this backed up and got rid of my taped-off-TV VHS)
In fact, because of the desire to have all the Gamera films in every possible presentation, here is what I believe the *minimum* you would have to have:
1. Gamera HD Bundle Collection [Blu-ray] (Gets you all Showa films in Japanese, and Heisei films in Japanese & English)- Mill Creek
2. Gamera The Brave [Blu-ray] -(Has both Japanese & English Audio)- Media Blasters/Tokyo Schlock *(wow! I was unaware this was OOP and going for more than $100 !?!)
3. Gamera: War of the Monsters Collection (A questionable collection, but gets you Gammera: The Invincible, and 5 other Showa films with AIP Dubs and opening/closing credits) - Pop Flix
4. Gamera, vs. Barugon, vs. Gaos, vs. Guiron, vs. Zigra (5 VHS tapes that contain the Sandy Frank Versions with opening closing credits) - Celebrity Home Entertainment
5. Gamera Super Monster (English Dub with Filmways Credits) -find a copy online somewhere or a VHS, or self-made DVD from someone who was fortunate enough to copy it off TV in the 80's/90's
Then, for other fans you have the following:
1. The Shout! Factory DVD's - Have some nice extras/commentaries on Gamera & Barugon. -Additionally- Gyaos, Viras, Guiron, Jiger, Zigra & Super Monster all come with their respective English Dubs (1 or 2 versions depending on the film), but retain the original Japanese opening/closing credits
2. Gammera The Invincible *The Neptune Media VHS* (despite being on VHS, this is still the acclaimed best presentation of this particular version of this film)
3. Gamera Vs. Guillon *The Neptune Media VHS* (an odd hybrid containing new English credits, the AIP dub of "Attack of The Monsters", but a restored uncut video presentation)
4. Gamera Vs. Zigra *The Neptune Media VHS* (I have never seen this, so I cannot speak to its contents)
**additionally Neptune Media released all 3 films in their original Japanese versions on VHS
Then Finally there is the Gamera MST3K collection on DVD From Shout! Factory (contains the 5 Sandy Frank dubbed versions with edits for time)
Additionally I am aware there are about a dozen other DVD releases of the Showa films, (licensed or not) I was initially just trying to list the *least* amount of money or DVD's/BRD's one would have to obtain to get all the versions of all the films.
There are no more good TV Shows, only ones that haven't disappointed me yet.