I have personally tested both... there is no doubt CG125 is way faster than GS150 till 100 km/hr.
The extra 25cc and bigger wheels gives the GS a higher top speed but come on guys..... who touches the top speed daily....haan but one can experience the superior acceleration of the CG everyday. In the real world CG is faster.
CG has the best sounding engine in Pakistan hands down (even the biggest GS fan has to agree with this), sound matters man. GS severely lacks in this department. It makes the ride boring.
GS has a higher riding position. Universally speaking low riders are considered better.....they look better and handle better. CG is lower than GS. Another win.
CG is more communicative than a GS, it responds to you with a seductive sound when you twist the throttle. CG has an aggressive character courtesy to its engine and stance. Don't forget the stance. Any other bike with a more aggressive stance than a CG is RX115, and that's 2 stroke. GS feels like a beefed up CD70........BORINGGGGGGG. CD70 and GS150 both are good machines......but they are just machines. CG125 is an animal!
CG deluxe has disc brakes at the front. The so called "modern" GS150 has drums......now that's hypocrisy suzuki!
Both bikes manages 40km/litres in the real world. Please note: CG125 ka average 25-30kmpl nahi hota. It's 40kmpl dear!
CG spares are readily available and cheaper than GS spares.
Electric self starter, brighter head lamps, new age wiring etc etc is what makes GS better than CG in this department. Question: Are these extras more important than everything I have mentioned above? A true biker at heart will never choose a bike for the extras........ Cake per icing tab achi lagti hai jab cake itself acha ho. Aur waisay bhi, these extras can be installed in CG.....magar GS can never get he same sound.....same acceleration....same smile on your face as the CG does.
Unfortunately GS is nothing in comparison to CG. CG is a legend and will remain a legend.