Noida Extension: Ready-to-move vs under-construction total cost reality check?

Spent the whole weekend crunching numbers for Noida Extension. I'm looking at Tata Eureka Park and Select Homes Mansion. On paper, Select Homes Mansion is super cheap, ready-to-move, but my broker brain is screaming 'hidden costs'. Tata Eureka Park, on the other hand, is under construction, way more expensive, but has that brand trust. I know how builders play with 'super area vs carpet area' and PLCs. What's the real total cost of ownership for Select Homes Mansion? Like, after stamp duty, registry, interiors, how much more are we talking? And for Tata, considering delays and potential for more hidden charges later, is that premium really worth it for 5-year appreciation? I work in real estate, but buying for myself is different. Need honest opinions on what other costs I should factor in for both.