In my app I close the connection when the app is backgrounded, and reconnect when the user resumes using the app. Meteor automatically deals with any changes that occurred while the connection was offline. In short, battery life has not been an issue.
If it really maintains an open connection for the duration of the app, then this will bleed power like you wouldn't believe.
Even if it's only when the app is not backgrounded?
I'd love to see evidence of that. I did some testing of the effects of websockets vs polling for iOS and saw negligible effects.
Were you testing it on WiFi or cellular?
The OS doesn't power down the antenna while there are open network connections. Did your tests wait long enough to turn off the antenna, was the test environment clean (i.e., nothing else using the network on the device, including your tests)?