[psanford]

If you are generating a new keypair, you should default to ed25519. There are still a number of openpgp/smartcard devices that only support RSA keys.

Edit: Another reason one might still use RSA keys: ed25519 isn't a FIPS-140 approved algorithm (yet).

[klodolph]

To be fair, “because it is FIPS-140 approved” is also a reason some people give for avoiding an algorithm.