Starting work on Signet 1.7.0 today which will introduce NIP-49 support (ncryptsec).
AES-GCM encryption will still be available and existing keys can be easily migrated with a single key press, but NIP-49 (XChaCha20-Poly1305) will be the recommended option moving forward. AES-GCM will be deprecated in the 2.x.x series but that is months away so plenty of time to migrate. It will also add key exporting (plain nsec and ncryptsec).
Signet will default to LOG_N=16 for the time being but will provide user configuration in a future release if you want stronger encryption. The NIP-49 spec allows up to LOG_N=21 but the memory requirements are higher than most users will want to spend (64mb to decrypt LOG_N=16, 3.2gb to decrypt LOG_N=21) for a signer.
This is probably above most people's heads but I'll do a long form article sometime near release, but there's plenty of documentation around on NIP-49 and its encryption choices.
Maybe the good folks at
@Nostr Compass can add some NIP-49 info to their newsletter in the mean time 😎