The firewall itself is basically the same...NAT and basic SPI.
The Belkin is a much newer router as far as generation goes, being one of the first "Pre-N/MIMO" routers....the Airgo True-MIMO chipset is a good performer. Came out a few years ago. The befsr41 is a very old design...pretty much one of the original first generation broadband routers that came out many years ago.