VPN.AC is owned by Netsec Interactive Solutions – a computer security company founded in Bucharest, Romania in 2009. Netsec Interactive solutions is a company whose employees are experts in computer security and cryptography. It is the only VPN provider, I am aware of, who is both ISO 27001 and ISO 9001 certified.
VPN.AC is on the smaller side of VPN corporations, but I believe it is in the Goldilocks Zone of VPN providers. With servers strategically located across 16 countries, it provides plenty of nodes, but is small enough that you communicate directly with the engineers who deploy and maintain its network.