My dad's old-school dragster has a gear drive because it has mechanical fuel injection and the fuel pump is mounted driven by the cam gear. Not to mention it's a solid roller cam engine that regularly sees 7,000 RPM in a pass.
For a street car, I don't think it's worth it. Just get a quality double roller. If you really want a gear drive, get one that's as quiet as possible.
My only reservation is that the motor is pretty much stock, and when everybody hears the whine of the gears, they will think I'm SC and want to run me, then tell everybody how they kicked the $#%^ out of a SC Mustang. Kinda' the "All show no go syndrome," but hey, I think they sound kick ass, and it's my car right!. But I can see where it could be annoying after a while though. But then again I go everywhere with the radio up loud.