Curious why you chose OpenVPN for your site-to-site links. I use it extensively for mobile VPN users, but for an "infrastructure" VPN, I use IPsec, which I find to be a much superior solution for that use case than OpenVPN.

Not the OP, but I've found OpenVPN easier to configure, and performance to be adequate. In what ways have you found IPsec to be superior?

Well the #1 thing for me is that the majority of IPsec functions are in the kernel and don't require that a userland daemon be running (which OpenVPN requires). Beyond that, I've just found that, while a bit more arduous to configure initially, performance is far superior and stability is better than OpenVPN.

Beyond that, pretty much every router out there supports IPsec, so if you're needing to integrate with other non-pfsense hardware, IPSec is often your only option.

Maybe it's just one of those "feelings" but i think it's way more flexible... :)

Chris Buechler the main developer is also hands down one of the most approachable and friendly people I've ever met.