It is very reliable.
We lose comms about 5 or 6 times during a 14 hour Pacific flight for 20 seconds at a time as the system changes satellites. That is using KSAK and NZZO.
There was an issue with a satellite fault a few months ago in the North Atlantic that cause a loss of comms in a small patch of airspace.
Last edited by c100driver; 4th January 2016 at 16:36.
Reason: spealing