I also worry when a site doesn't work with autocomplete. It's rare these days that the developers have actively tried to prevent it from working, but more common that an unnecessarily intricate sign-in flow makes the existence of the password field unrecognizable to the browser.

This makes me wonder about the personal security practices of the team that built it -- it's unlikely they typed strong passphrases hundreds of times a day during development -- and whether a secure site could come from such a team.