As a technician at firealarm.com, I can shed some light on this. The Edwards G4SVRF is indeed a significant upgrade over the G4HFRF-S2VMC. Firstly, it boasts enhanced sensitivity and accuracy in detecting fire hazards, thanks to its advanced sensor technology. Additionally, it offers improved connectivity features, allowing for seamless integration with modern fire alarm systems. Moreover, the G4SVRF is designed with increased durability and reliability, ensuring long-term performance in various environments. Overall, the G4SVRF sets a new standard in fire detection and safety, making it a worthy replacement for its predecessor.