After 19 days of using VPN on Google Cloud Platform, I want to spread more information about their excellent service.
Previous VPN services I tried where very unstable for me - even 1 disconnect per hour is not acceptable for me, because when it happens it happens in the wrong moment and it's very annoying.
Then I tried OpenVPN on own Linode VPS, but was wonder to still see disconnections, although less often - once per 2 hours approximately. I suppose Linode have some issues in their London DC network (and tests on speedtest.net confirms that). Next my try was same-sized VPN on DigitalOcean (Amsterdam 2 DC), and connection was more stable. But still few disconnections per day. Have to say, performance of same size server is much better on Linode. They just need more stable network.
In 19 days of usage VPN on Google Cloud Platform I've encountered... 0 disconnections. It wonders me and I'm glad to share my how-to (copy of my answer on serverfault.com).