I use IPsec in addition to OpenVPN, primarily because that's all iOS used to support. Since iOS 5 or 6 (I think; maybe even as late as version 7?), Apple has allowed third-party VPN apps, so with an "official" OpenVPN client now available in the iOS App Store, it's not as important as it was. However, I've left it running as a fallback solution to OpenVPN (some hotel firewalls, for example, permit IPsec but actively block UDP-based OpenVPN).

I use ipsec-tools, as circa 2012 when I was originally setting this up, it was the only free software IPsec solution I could get to work with iOS clients, but based on this vulnerability I've now disabled it and will try StrongSWAN again.