Can you explain what makes it better than venerable old OpenVPN?

Mostly speed, a more minimal configuration syntax, more modern crypto.

OpenVPN works fine, is quite portable and runs in user space. It's quite a lot slower, but is well-tested and can be managed with a Certificate Authority in organisation where that's desired.

I presume speed on linux? Otherwise doesn't wireguard suffer from the same peformance drawback than OpenVPN on windows (running in user mode)?

OpenVPN is quite configurable, not as much as IPsec, but still a lot, and (from what I hear) has quite a bit of code bloat. I believe that userspace WireGuard has better performance than OpenVPN.

My understanding (and experience) is that OpenVPN on windows is structurally capped at about 5-10 MB/s. I was curious of how that compares to WireGuard.

Performance issues with OpenVPN on Windows arise out of the inefficiencies of the TUN/TAP driver, not the OpenVPN software itself.

I am sure that's true, but unless there is an alternative driver I am not sure why that makes a difference.

Thomas Ptacek does it better than me: https://news.ycombinator.com/item?id=14599834

Do you only use it to connect remotely into your home network or are there VPN Services for wireguard available?

I use the mullvad VPN service for wireguard. They currently have 44 wireguard servers active around the world.

I second this. I remember reading an interview with one of the mullvad staff saying "y dream openVPN config would be [insert more or less verbatim the wireguard spec], but due to the nature of openVPN that either won't happen or will take a long time". They were quick at adopting wireguard :)

They are very knowledgeable and spend a lot of effort in securing their VPN. I contacted them about what I thought was a bug, and got a very thorough answer about why mullvad behaved like that, what kind of threat it mitigated, and how I got the behaviour I wanted together with things I could do to keep safe (which was to update the kernel). Within 6 hours.

I am a very happy customer.

Azire gives free WG access while in beta

I second Azirevpn.com! Great speeds