You are smart to ask these questions. Reliability is a serious topic that http://www.pubnub.com fits in. I work at PubNub and believe it is the best offering for reliability and uptime being a globally distributed service. During the EC2 outage on the East Coast USA, we lost our servers there. However! Our automated redundant routing system transferred traffic to the surrounding nearby healthy data centers. Customers didn't notice the switch, and went about their day.