When I went from lastpass to bitwarden I could simply export all my passwords to a json file and import them to bitwarden. I think it took like five minutes or something like that.
I recently migrated from 1Password using Dropbox for sync, to KeePassXC (Windows, Linux & Mac) and Strongbox (iPhone & iPad) still using Dropbox.
Migration was a simple matter of exporting a CSV and then just correctly selecting the column order for KeePass import.
For those who don't want to trust a third party, even with their encrypted data, I believe that home NAS sync-when-available is possible - I personally haven't tested the implications of syncing changes from multiple devices at the same time in that scenario.
I exported successfully from 1Password 6 onto Secrets and KeePassXC. Only thing missing were software licenses (some attachments may not carry over correctly or show up as notes).
I imported from 1password. I found the following problems.
- Some items did not import correctly at all because the 1password export format did not quote values (CSV). This means that if I have a password with a comma in it, I get two broken entries. This is more of a 1password issue though.
- 2FA tokens did not import and would have to be manually reset. I guess this is to be expected though.
- Some fields had different names than bitwarden was expecting, so values were imported into the wrong destination and had to be manually corrected.
This was a while back so I'm not sure if anything has been improved.