I don't think you can really compare these three like that. I mean, at the risk of playing the devils advocate but without vanilla Minecraft you'd never be able to enjoy a resource pack :P

I also wonder: "Better for what?".

I'd have to say Vanilla and Mod Packs, since I can really do either, it all depends on my mood for the day.

I only use WorldEdit as a mod, otherwise I'd use good ol' Vanilla Minecraft

Mods? What about shaders guys? 0:

Honestly, you can't really compare game editions to changing the game's textures, it's really not comparable.

Most mods are unbalanced and don't fit well with vanilla minecraft features. There are a couple good ones though. I am currently involved in the datapack-making community (vanilla commandblock mods) and I feel the features in them are a lot closer to what you want. Also, they are installed per-world and don't require configuring custom versions.

The most popular texture packs are all the ones that try to keep vanilla designs with more detail, so they don't do that much to change your game.