Hidden value in Noida Extension's completed projects?

My own possession in Noida Extension was in March, making me rethink 'ready to move' projects. Now helping a relative, I'm comparing Capital Green Avenue 74 and Elkens Sai Dham Residency. What's the real carpet area efficiency like for these two? Is Capital Green's higher price truly justified, or does Elkens offer better value regarding actual usable space?