I`m planning to move to portable releases of Blender and I wonder, will I have to reset every new version manually, or will it import settings as well?
I don't think it will include manually installed addons, but I could be wrong. You can import settings from any Blender version that previously ran on your machine. You should also be able to import options from any machine a portable drive is plugged into. In windows the settings are stored under %appdata%\Blender Foundation\Blender<version number> The first time you run any new Blender version it will ask you if you want to import the settings from the previously highest version that has been started at least once with that current installment of Windows, independent on whether you installed Blender, or ran a portable. You can also manually import keymaps under Edit -> Preferences -> Keymap