I use icloud Keychain on Mac, and it works well for me as it saves not only passwords but bookmarks too in the cloud, so less work if reinstalling the OS. Just this week I tried some apps, but I did not find many advantages of using them.
While I used Chrome in the past, I used Chrome synch, it worked well too. I think Firefox has some similar tool. I am not familiar with Ubuntu, but probably browser solution could be ok, as it synchronizes passwords, settings and bookmarks across devices.
For my needs, the integrated solutions work the best, as I prefer simplicity. Any third party app just added additional step/requirements for me, what is not my cup of coffee