Noida investment: Sector 21 or Greater Noida West?

Guys, I'm looking to upgrade to a 3BHK in Noida for my kids' school. Wife wants a good society, safe for kids. Budget is tight, around 1.5Cr. I've been considering Sector 21, but the prices are high. Greater Noida West seems cheaper, but is it worth the compromise on connectivity? Has anyone compared Sector 21 with new projects in Greater Noida West recently? Which one will give better appreciation in the long run? Also, what about under-construction vs ready-to-move? I'm scared of RERA delays. What's your take on Adarsh Group projects? Any advice? Kya karein?