I came here to see if the final rankings had been documented anywhere and saw that they hadn't, so figured I'd do it myself for the benefit of anyone else interested. I'll also include notes crediting the guest reviews, references to port comparisons, and names of games reviewed within collections where not obvious from the game title (he makes a point that the other non-shmup games included won't influence his ranking). Without further ado:
S+
Spoiler
Layer Section a.k.a. Rayforce (guest review by Boghog)
Radiant Silvergun (guest review by Mark_MSX) - says it's the definitive version thanks to lowest lag over Xbox 360, Steam & Switch
Spoiler
Cotton Boomerang
Dazaemon 2
Panzer Dragon Zwei (guest review by Spiders_STG)
Salamander Deluxe Pack Plus - says Sat = PS1, no notable differences beyond slightly grainer FMV intro on Sat
Sexy Parodius - says Sat = PS1, any differences are "just nitpicking"
Soukyugurentai - says Sat > PS1 as the latter has issues with slowdown and arcade inaccuracies
Thunder Force V - says Sat > PS1 for visual issues on the latter
Twinkle Star Sprites (guest review by Pearl)
Spoiler
Fantasy Zone (guest review by Pearl)
The Game Paradise!
Gokujo Parodius Da! Deluxe Pack - says Sat > PS1 since PS1 has some odd resolution cutting on Da. Both games individually are S-tier but lack of extras from the SFC version in Da! and no button remapping ("inexcusable by this time") marginally lowers the score
Jikkyo! Oshaberi Parodius - says Sat = PS1 and both preferable to the SFC original; doesn't make any comparisons of the exclusive content (Extra mode vs Accident stages) between ports
Metal Black - says it's the definitive home conversion due to visual issues on PS2
Thunder Force Gold Pack 2 - notes audio reproduction issues on IV but extra ship and removed slowdown gives it at least arguable value compared to the MD original
Spoiler
Detana Twinbee Yahho! Deluxe Pack - says Sat = PS1, no noticeable differences, would rate Detana an A- and Yahho an A+ alone and the only thing stopping the collection getting an S is the lack of Tate mode
Gradius Deluxe Pack - says Saturn = PS1, but lack of extras and his preference for the PC Engine versions drops the ranking
Guardian Force
Gunbird - says Sat > PS1 for actually including Tate
Hyper Duel
Image Fight & X-Multiply - says Sat version has scaling issues in Yoko not seen in the PS1 port, otherwise no differences noted
Konami Antiques MSX Collection (guest review by ShmupsBR)
Night Striker - says Sat > PS1 due to better draw distance and extra content
Sengoku Blade
Strikers 1945 - says Sat > PS1 for slowdown on the latter
Thunder Force Gold Pack 1 - notes audio issues compared to the MD originals
Wolf Fang
Spoiler
Shienryu
Spoiler
Gun Frontier (guest review by Ak's Arcade)
Sonic Wings Special - says Sat = PS1, except for the PAL PS1 version since it doesn't save your progress
Strikers 1945 II - says PS1 > Sat for oddly large hitbox on the latter
Tempest 2000 - says he probably prefers Jaguar > Saturn overall as the changes aren't necessarily upgrades
Spoiler
Bokan to Ippatsu! Doronbo Kanpekiban
Capcom Generation Vol. 3 inc. Exed Exes, Vulgus, Son Son
Capcom Generation Vol. 4 inc. Gun.Smoke
Galaxy Force II
Kyukyoku Tiger II Plus
Panzer Dragoon (guest review by Spiders_STG)
Williams Arcade's Greatest Hits
Spoiler
Darius II (guest review by Bofner)
Donpachi (guest review by Mark_MSX) - says PS1 > Sat by a small margin for better graphics and sound
Gekirindan - says the arcade game is a B+ but let down by a poor porting job
Skull Fang
Steam Heart's
Spoiler
G-Vector
In The Hunt - PS1 > Sat for the latter's horrendous slowdown
Midway Presents Arcade's Greatest Hits: The Atari Collection
Spoiler
Layer Section II a.k.a. RayStorm - says it's an S-tier game but PS1 > Sat due to issues with transparencies, slowdown and audio on the latter and better exclusive content on the former
Spoiler
Sol Divide
Space Invaders
Spoiler
Terra Cresta 3D
Spoiler
Spoiler
Shmup Salad - says it's "the best of these homebrews"
Sky Blaster
After Burner II & Space Harrier - says these are the most arcade accurate home conversions
Mobile Suit Gundam - says not really a shmup, and not really a good game either
Keio Flying Squadron 2 - says not a shmup but contains shmup stages, though not a scratch on the original
That said, Mark_MSX's review of Dodonpachi stands out as overly harsh. He's entirely correct to point out the substantial arcade inaccuracies, but it would've also been nice for him to give his standalone thoughts on what he calls the "Saturn Arrange" - rather than just making the same observations from his earlier port comparison video and writing it off entirely. No way is it worse than Steam Heart's
