I migrated my 100's of Web logins from 1Password into Keychain yesterday ( quite a long process! ) using my Mac, and then tested it on my iPhone. Then I tested it on my iPad by spot-checking logins that I had added. Problem 1) none of them were there. Fix: I fixed that by logging in/out of iCloud on my iPad. Afterwards, the newly added accounts were there. Problem 2) I navigated to Macrumors and tested to see if it would prompt me to use the stored password. Nothing. I navigated to Macrumors on my iPhone, and it prompted me to use the stored password. The problem turned out to be that I was using a Smart keyboard with shortcuts disabled in Keyboard settings. Fix: I turned shortcuts on and tested the login again. The shortcut bar appeared and prompted me to select which credentials I wanted to use to login. WIN!