First home worries: Noida RERA reality check

What's the real deal with RERA registration for projects like Jaypee Krescent Homes? I'm looking at a 2BHK in Sector 137, budget around ₹75L, and my agent mentioned Radhey Krishna Techno Build Pvt. Ltd. for another option. Honestly, I'm finding it hard to verify if builders are actually RERA compliant beyond just seeing a registration number. Are there specific red flags to watch out for on the RERA website itself? And if a builder delays possession, which I hear is common in Noida, what are my actual legal options under RERA? Is filing a complaint truly effective, or does it just add to the wait for resolution? I'm really trying to avoid legal traps as a first-time buyer. Any experiences with RERA disputes here, especially around getting refunds or completion?