AWS VPC with AWS VPN Client vs. OpenVPN Access Server

Using a VPN is the best solution to provide encrypted traffic between a remote client and a remote workload, systems, and data.
You have several choices:
AWS Client to VPN — This provides the flexibility of connecting from anywhere in the world, the infrastructure will be managed by AWS. In the event of an AZ failure, you can migrate to another AZ easily.
EC2 VPN (such as OpenVPN) — Provides additional feature ranges, however, you are entirely responsible for scaling and managing the instance and any other failures.
I would opt for the AWS-managed solution primarily because it mitigates the risk of AZ failures removing your access to the cluster. You can reduce your costs of using this option by scripting to shut down client VPN connections out of hours.