I have been using OpenVPN peer-to-peer between two residential sites for about 5 years. The only time I have had any issues is if the ISP connection fails, but, like I said, it automagically re-connects when it sees the connection is available again.
As for the OpenVPN service failing, you could set up Service Watchdog, which monitors other services that you tell it to and it will restart the service if it sees that it has failed.
I have found Service Watchdog handy for DNS and DHCP services as well.
Be sure to set up e-mail notifications so you know something was addressed by the watchdog service.