I've been running and installing gear drive setups for years. As long as the crank runout is within spec, gear drive is fine... Pricey, but fine.
On my new 124, I'll be using late model roller chains (inside & out) with TMan cams setup like 07+ models on the outer end and 06 & older on the inners. There are several vendors offering popular grinds this way now (TMan, Andrews, Bob Wood). There are also place you can have late model cams "converted" to the hybrid style for the older bikes.
You can buy the conversion kit from Andrew, TMan, or Wood. You can also get the individual component p/n's from an 07+ parts manual and order them individually from your favorite online HD source, and them buy which ever cam grind floats your boat...