Noida Extension vs actual Noida: where's the growth?

I'm thinking of investing again. Already have a 2BHK in Sector 156. Good rental income, but appreciation is slow. Noida Extension looks tempting, but scared of the builder delays. Gold Homes Infra Pvt Ltd ka rate sahi lag raha hai. Is it worth the risk though? Sector 156 is safer, but ROI is lower. Should I just stick with what I know? What's everyone's experience with Noida Extension appreciation? Any advice?