RERA: Is it just for show, honestly?

Did a site visit to Sattva Lake Ridge in Kokapet last weekend. Builders wahi marketing spin de rahe the, but I'm looking for my own place, so thoda careful hu. I know what builders don't tell you. RERA registration check karna kitna effective hai, especially for projects like this? Aur agar builder delay karta hai possession, like Salarpuria Sattva has sometimes, toh RERA complaints actually work or just on paper? Bina OC ke possession lena kitna risky hai? Hyderabad mein kya experience hai logo ka?