I (38) was having a conversation with a younger coworker (28) about vintage anime that I would recommend for him to watch. I brought up Bio Booster Armor Guyver because it was the first anime that I really got into. Even had the translated and mirrored manga that you could only get a comic book shops.
Might be a bit difficult to find if you're talking about the 1990s Guyver OAVs with the campy dub (I just sold off a partial set of VHS tapes of that, so I had to check up on it). There was a DVD set, but it's out of print. The TV series from 15-20 years ago is more readily available, I think, but the dub is less fun . 😉