Is it better/different than https://tailscale.com/docs/features/taildrop ?

Taildrop looks good, I didn't know about it.

But it's more for when you already use Tailscale, which relies on a central server and someone who "owns" that network.

In Flipflop you don't need anything besides the app, and each two peers form a "network" of their own, with no owner and no management.

It is better in one way: Taildrop supports iOS.

iroh is different and more than just a vpn, where you use a bunch of tools together, you can do it all in iroh with one identity, the tunnel, the file transfer, the ssh access, and others. Look at tunnet for example https://github.com/tunnetio/Tunnet to get a better idea.

Better, who knows. Seems different in that Flipflop uses P2P connections directly to the peer, alternatively via other available peers (and initial connection might use central signaling server), while taildrop seems to depend on a tailnet, which is typically hosted by Tailscale (unless you run that yourself).

I guess it's a bit like comparing WeTransfer with Airdrop, one tries to use the network they're on already (internet) where the other favors local-local connections.