Gear drives were relevant in the 60's and 70's when timing chains were crap. The old chains were prone to stretching, and when it came to advancing/retarding the cam, required that you drill the big gear, and use a offset bushing to move the cam one way, or the other. A real pain in the ass. Now there are billet sprockets , with multi-indexed crank gears, that make degreeing the cam way easier. High strength, true roller, double row timing chains that don't stretch at high rpm and allow cam timing to change with it.
Gear drives have always had a bad rap,...as they induce bad harmonics as a side effect. They do this because a chain acts as a damper to isolate those bad harmonics.
Now, for all but the more serious effort race cars, a chain will be more than sufficient. A more dedicated effort race build usually gets a belt.