OHV engines are obsolete and donot provide better valve timing as compared to SOHC or DOHC ones...
Provided that OHC and OHVs are made of equal quality an OHC shall require less maintinence and would prove more reliable and powerful. CG uses a good quality OHV which has potential to out perform poorly made OHCs by competitors. (Please note that those OHCs are also 70s-80s tec mostly) Otherwise nothing is better in OHVs or CG's engine.
OHVs consume more fuel, vibrate more, have poorer valve timings, have lower topspeeds.
OHVs have no timing chain instead they have push rods. OHVs also dont easily support multiple valves per cylinder.
OHCs also mainly support only 2 but DOHC can support more. Likewise VVTI (Variable valve timing interllegence) or VTEC (Variable valve timing and lift electronic control)engines by Toyota and Honda are advanced versions of DOHC with further improved and precise valve timing for better acceleration and high end speed.
Although there are also many modern day examples of OHVs, mainly in american cars that rely on more brute force than refinement... eg: dodge viper, dodge ram etc.