FBX or OBJ Models (Importing)

Is there any advantage to importing an FBX over an OBJ file of the same model ?
I download most of my models and they are mainly in Blender format.
I open them up in blender them export to OBJ and FBX just incase one doesn’t import or something.
I always seem to try and import the OBJ file first as it is usually the smaller of the files.
It seems like some files take forever to import and some just take so long I ctrl alt delete and restart project. Some come with textures and some don’t. I always choose to import textures.
So, all this being said I have a few questions if anyone would be kind enough to help me out.

  1. Should I use FBX or OBJ (is one better than the other ?)

  2. Why do some textures import with the model and some do not ? (I understand I need to import them separately sometimes but WHY ? Is there a way to prevent this in future imports?)

3.Sometimes I import models to UE4 and they have Extra planes/flat objects just floating around, I delete these in blender before I import them now to prevent this. (IS THAT OK ?) (Am I breaking something ?)

  1. Since My FBX files are usually bigger than my OBJ files, does that mean they are better quality ? (The bigger the better ?)

5, Why does it Say FBX Import Options when I import an OBJ or File instead of FBX ?

Thank you very much for taking the time to read and answer these questions.

Scott

Unreal Engine 4 highly supports FBX files for importing content/animation/materials and so on into the engine. So yes, you should try to use FBX files instead of OBJ.
https://docs.unrealengine.com/latest/INT/Engine/Content/FBX/index.html

Greetings

Thank you very much for your answer.