Anyone tried J:COM’s new fiber (hikari) service? Worth upgrading or just sales talk?

I use J:COM right now, and the connection in my building has always been pretty unstable, so I was already thinking about switching providers. I also had Disney+ bundled through them, but with the price hikes I recently canceled that too. Just as I was comparing other ISPs, J:COM suddenly called and told me they now offer a “new” fiber‑optic (hikari) option for my building, apparently for a little extra each month, with the promise that speed and stability would finally improve.

That’s why I’m trying to figure out whether this is actually an upgrade or just retention sales talk. Has anyone here used J:COM’s newer fiber service? Did it genuinely improve your speeds and stability, or is it basically the same old J:COM under a new label? I'd love to hear real experiences before I decide whether to stay or switch.

by SilverFoxJp