ThunderStore is it for me. Never used Nexus (ok I downloaded the HD textures there once), since I don't like to register just to download a few mods.

ThunderStore is easy, configures everything for you, resolves dependencies and notifies you of updates for mods that you then can install if so desired. And it has the store included (as the name implies) so you can browse through mods to your hearts content. And you can run the game vanilla if that is your intent.

AND you don't need to register.

Highly recommended.