You may be wondering why some mods aren't in the guide, or are looking to add your own mods. If so, please reference this list:
ENB: ENBs were never fully developed for New Vegas like they are in Skyrim. They come with a fair share of technical and performance problems, such as broken AA and transparency bugs. They also use loads of vision-obscuring affects such as depth of field, lens flares, and chromatic aberration to obscure the bad AA and LOD, which makes them very hard to play with. They also break some of NVTF's improvements
Higher resolution versions of the guide's texture mods, for example Ojo Bueno: The texture sizes in the guide were picked for the best performance/visual fidelity ratio. Higher texture sizes will yield barely any visual difference (you will only notice if you are looking very carefully at an object up close) but can have a noticeable performance impact. The engine also can't handle a majority of the game's textures being 2k with 2k bumps/normals, which is what NMC/Ojo Buenos' high presets have. You will have unavoidable stuttering/crashing with those
Charge's HD Texture Pack: Generic AI-upscaling that results in a very minor visual increase for a potentially large performance decrease. Upscales files that shouldn't be upscaled such as normalmaps and glowmaps, which can cause texture artifacting making the textures look worse
Asurah Reanimation Pack - Incompatible with Weapon Mesh Improvement Mod (if you don't use WMIM you can use Asurah's, but it has its fair share of bugs on its own and isn't supported/recommended
EVE: Also Incompatible with WMIM, and many other mods. Also can cause noticeable performance issues. EXE does everything EVE does except for the energy weapons, but with a much lower performance cost
Handheld Pip-Boys, such as the 2500: All share the same frequent bugs, such as the Pip-Boy being tilted and you holding your weapon on the wrong side of your body. If you want to use a Pip-Boy replacer, use either the 2500a or 2000 MK. VI
Project Reality: Very old/poor scripting that will cause massive performance issues and bloat your save
Fallout Character Overhaul: Very buggy (multiple broken/wrong filepaths that result in missing meshes and/or pink skin), the installer is broken, doesn't cover all NPCs (and all DLC or mod NPCs) so the uncovered ones look very out of place, and I also want to add that I think it looks incredibly ugly
Interior Lighting Overhaul: RWL Tweaked includes its own, much simpler interior lighting overhaul at no performance loss (ILO could cause FPS loss in large interiors such as Camp McCarran). ILO also has some interiors that are 'bugged' and are straight pitch black and unaffected by night vision
Electro City: A Little More Lamplight is much cleaner and simpler. Electro City includes much un-needed bloat such as new NPCs and boxes of Cateye. Also seems to have remnants of a planned quest left over in-game