3BHK hunt in Saket/Dwarka: Quality and hidden costs?

My current 2BHK in Vasant Kunj feels small, so I'm eyeing 3BHKs in Saket or Dwarka, around ₹3-4 Cr. Looking at Godrej, DLF, and Tata Housing. I'm worried about actual construction quality after a few years – plaster cracks, seepage? Also, how transparent are they with hidden charges like PLC or maintenance deposits at possession? Heard horror stories. What's the real word-of-mouth on their post-possession quality and customer support? Any experiences with Birla Estate projects in Delhi?