Firstly, I initially purchased the device to build a VPN, and one very valuable feature for me was the ability to create a layer two VPN, which was available on the legacy ER router. It allowed me to expand a subnet to a remote site, which was essential for my setup. Additionally, I appreciated that the CLI of the router was similar to other Juniper products that I was familiar with. As for my current setup, I'm using it as a wireless controller and a camera DVR. I plan to purchase newer-generation routers for building VPNs between sites. However, my infrastructure running on the ER routers is sufficient for now, and I haven't faced any issues requiring replacement parts. I am also happy with its performance.