Hidden realities of Gurgaon builder timelines and quality

Spent the whole Sunday checking out options in Sector 65. We need a 3BHK for the kids, school admission is around the corner. Visited some M3M and Godrej projects. Honestly, I'm worried about construction quality – sunne mein aaya hai ki plaster cracks, seepage issues aate hain after possession. On-time delivery ka kya scene hai? Builders promise a lot, but actual handover kitna late hota hai? Also, customer support after booking... do they even pick up the phone? Kisi ka experience hai with M3M ya Godrej on these points? Kaun sa builder sahi hai for end-users like us?