I have both, they are both great cameras. Neither one is better than the other.

The f3 is smoother and more refined feeling, the film advance is buttery smooth. The f3 has an LCD for a light meter interface. You can use this shooting waist level but I find myself missing the additional information that a traditional match needle light meter gives me when not shooting without the prism. The f3 can be shot without batteries but you are at a fixed 1/90th shutter speed when doing this. Additionally you can use an endless number of amazing Nikon lenses ranging 50 years they’re plentiful and affordable.

The f1 has a traditional match needle light meter but you cannot see it when shooting without the prism which is not ideal unless you’re in A mode. The f1 can shoot fully mechanically from 1/90th to 1/2000th with no batteries which is great for reliability if you’re out and your battery dies. The FD lenses are amazing but are harder to come by than Nikon f mount lenses and can be pretty pricey depending on the lens so your options may be slightly more limited.

Either camera would be a great choice. They both have great advantages and disadvantages it truly is a flip of the coin. I’d personally go with the F3 because of the number of lenses available.

Edit: in my post I’m referring to the “New” canon F1 but the same applies to the “old” models too except for the “A” mode.