Thanks for the additional replies folks, I had thought there would be no further responses to this issue and had sorta resigned myself to going back to Unity since when loading my meshes there, they looked exactly the same as they do in Substance Painter etc…
Thing is, in the early days of UE4, I got the same experience - new scene, load model, looks exactly the same, now they’re black.
I agree, it is probably environment reflection because I usually always start from a blank scene and work up from there.
So this lead me to the same conclusion that there wasn’t an environment to reflect etc.
As my first test, I created another blank scene, and using basic cubes, I created “walls” around the scene - something for my model to reflect.
No joy, still mostly black. This this IS with reflection probes and boxes in the scene! 
For my second test, I decided to load one of the default “populated” scenes, I believe it was the first person blueprint scene (still wo/content) and I noticed the model looked somewhat better, but still not nearly what I was seeing in Unity or Substance.
Still wasn’t pleased with my results…
With my materials, the model always looks GREAT, up until the point I add the metal channel texture (whether all white or with varying gray etc.)
This had me suspecting that my material setup wasn’t correct (perhaps I need multiply something w/the metal etc.,) over simply directly connecting base color, AO, roughness etc. Though again, back in Unity, doing the same, everything looks as expected.
I HAVE TO figure this out, I can’t see myself NOT being able to use UE4 - all the new Cinematic and Matinee features alone has me drooling over the idea of creating my cut scenes using those features over using pre-rendered animations as I had planned in the past!
Everyone else appears to not have this issue I’m experience, so obviously it’s something I’m missing in setup; all 3 of my computer (laptop, desktop and work) show the same result, so it has to be something I’m missing.
I just installed 4.13 and I’m going to fight though this again - I have to get back to how it was when I first started using UE4!
This time I’m going to create one of the “functional” Blueprint scenes and LOAD the content to get me started - hopefully I can get past all this with refocused effort…
Are their any downloadable (or default setups) you can recommend that I try where you don’t have “black” issues with your models? Any pointer would be appreciated!
Again, thanks for all your responses guys, hopefully I’ll figure out what I’m doing wrong…