I have an M3, two M4's, and an M6. I can't say that they are superior to a Nikon F in any way other than that their winding action is a little smoother, and that they may focus better in low light. But the M cameras are not as reliable, cannot focus closely, and don't allow you to see exactly what the lens sees.
As far as weight is concerned, an F with an eye-level meter weighs roughly the same as a Leica M. I like to shoot with a 28/2.8 AIS lens, which weighs about the same as a 35mm Summicron, but less than a 50mm Summilux.
If your goal is to simply take good pictures, then the F is the obvious choice. You can spend the hundreds of dollars you save on good lenses or film.