another useless debate comparing 2 very different motorcycles. You can't say if one thing's better or the other based solely on the technology they're using and their technical specifications. That just means you care about numbers rather than the experience of the motorcycle. donon motorcycles chalao, aur dekho ap ko konsi motorcycle behtar sensation deti hai. Unfortunately even senior members here bash the motorcycles that they do not own in favor of their own motorcycles. Aur jab baat haath say nikalti hai to beech main numbers daal detay hain. Trust me, technical numbers don't matter in real life. What matters is how the bike makes you feel.
If you're concerned about fuel economy etc, get a 70 or 100cc bike, 125 and 150 will disappoint you cuz we expect 60+ kpl from all bikes here.
I haven't driven piaggio so cannot comment on it but i have driven the GS150 and for a small-time rider like me (i have a 110cc bike), it was sensational. the pull from its engine on hard acceleration was addicting, and the drivetrain noise of the engine is a delight to my ears.
if you cant decide what to get based on forum discussions and technical numbers, drive both bikes and decide for yourself.