I'm running Windows 8.1 and a fresh install of Fallout New Vegas with no mods so far. I've stumbled upon a weird issue that I haven't encountered or read about before. I know this didn't really answer your question but I hope it helps. Before I ramble on too much longer: you will have to make the decision yourself as to if you would like to use both with some issues cropping up occasionally or stick to one or even neither to prevent said issues.
However, it is Ess' guide and I feel as though my concerns have already been stated and that it is his choice in the end and I don't want to cross boundaries.
I could write a long argument as to why I think NVR3 should be taken out of the guide. Though the author of NVR3 will claim that it is 100% compatible with FCO, I have found in hours of playing that this only causes mis-matching faces and bodies. The ideal thing would be if someone made a compatibility patch for the two mods.
This is why I stick to only using one of the beautification mods. For me personally the issues are too immersion breaking for me. However, my main point is that if you use FCO and NVR3 together you will have some strange issues popping up here and there.
I know I am sounding like a broken record at this point, and most people don't agree with me.
