I run both pfSense and OPNsense, one on each side of my IPSEC tunnel. The pfSense since 2018 and the OPNsense since 2021, when pfSense looked like they were moving away from the open source series (that is now at 2.7.2).
It was a win-win to be able to explore both. OPNsense feels a little bit less reliable because they often release (once or twice a month), but also often break things (it was always possible to solve this pretty fast, or patches appeared).
I do not have a preference for the interfaces - I feel like I am finding things faster in pfSense, but that may be because I simply used it longer. Both are quite good.
pfSense is slow to adapt features (e.g. Wireguard), but concentrates on the important basics. It is a solid software that never left me, it never crashed and survived where I expected otherwise.
Given that I trust OPNsense a little bit more (because the maintainers communicate their goals clearer), I am planning to slowly phase out my pfSense and first move it behind another OPNsense box, as an internal second barrier behind my public WAN net. This may change though, I am planning the migration phase to happen between 2025-2027. Right now, it feels good to have both worlds.
