Noida builder hidden charges dilemma

What's the actual construction quality like for ATS projects in Noida, specifically Sector 150? I know what builders don't tell you. My last client got hit with huge hidden charges from Godrej in Sector 78. Are ATS's post-possession maintenance charges fair, or do they spring surprises? Honestly, I'm tired of the runaround. Is their customer support even responsive after booking? Buying for myself feels totally different.