I work for a company that provides a product that tries to make IPsec a little easier and I can say like 80-85% of our support burden is helping our customers configure their ASAs, Junipers etc. to talk to our cloud based VPN concentrator/router/app firewall. We basically run people through a checklist [1] and it is non-trivial. IPsec can be a real pain.
[1] https://cohesive-networks.s3.amazonaws.com/dnld/Cohesive-Net...