Keychain uses AES256 so it's about as reasonably secure of a single-password solution as you can get (given you use it correctly). I would assume 1Password is equivalently secure.
The choice of encryption algorithm only lets us point out which systems are broken, not which ones are secure. A secure system could never use ROT13, but a broken system could definitely use AES256.
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Is 1Password more or less secure than Keychain? If my 1Password is unlocked can any application get passwords out of it?
That's an interesting question. 1Password isn't as integrated as the Keychain, but in both cases you have to manually approve access.
1Password is more portable though - Keychain is only useful in MacOS X.
Keychain uses AES256 so it's about as reasonably secure of a single-password solution as you can get (given you use it correctly). I would assume 1Password is equivalently secure.
I'm less worried about the crypto algorithms used than what's available decrypted and when.
The choice of encryption algorithm only lets us point out which systems are broken, not which ones are secure. A secure system could never use ROT13, but a broken system could definitely use AES256.