nightcraw1er.488: Fair enough, I had assumed the BFG edition was a GOTY edition with all the bits patched up and final. Will stick with my separate copies.
Everyone's entitled to get whichever one they prefer, except in this instance regarding BFG I would suggest one looks into the differences between the two versions. The BFG edition does have things which the older doesn't like support for 3D headsets (which is there because Carmack was interested and playing with VR/headsets, before going to work for....Oculus VR) . Though it's mod support has been very much kneecapped from what I remember including not being able to use most existing mods without having to fix them and not supporting some at all, some modding is now pretty much impossible compared to the original if I remember right.
Unfortunately I don't remember all the differences and details so I can't list them with certainty here for others convenience, though I do remember being excited when I first heard about a "BFG" edition only to be more and more disappointed the more I found out about it and being frustrated by how they were removing and breaking things (literally, it has new bugs) only to add a few other things I personally had no interest in and I'm not sure how much things have changed since then.
A quick search should turn up some information, I quickly found some promising results and something on
Eurogamer which could be summed up as saying it's the new console version of Doom 3 (FOV, brightness etc changed for TV viewing). Which kind of ties into my old suspicions of it being little more than a tool to drum up interest in what at the time was the upcoming Doom 4, they do make more money on the consoles afterall.
Basically I would suggest going with the old version and trying out some of the loads and loads of mods for it, even if it's one's first playthrough there are graphics mods that will keep the game as it is but just be much better looking (some of the original Doom 3 textures were a joke and BFG keeps to that joke).
To get an idea of what you could mod the original into graphically an image search for Doom 3 Wulfen will probably make your jaw drop and your PC cry out for mercy if it can run it.