Sorry about the absence guys, I know its been awhile.
This release won't include push notification, we're still polling. However, we are actively looking into it. The issue with push is, unlike apple, android apps must provide their own push back-end, and CD2M requires Android 2.2, we have supported Android 1.6 in the past. This release will only support 2.1+. Once we have Android 2.2 as our minimum support we'll definitely be in the right place for push notifications.
Something like this ^^^ is common, but we've evolved to a fairly efficient system over the last year+ that we've had alerts.
Our polling doesn't have to do a search, all the work is done on the server just like push notification. The only difference is, with push notification, the phone maintains an open connection to the server and the server does the polling at a faster interval while the phone waits. With polling, we just check back with the server every 3 minutes. The battery usage is nearly zero. What you may see is some "wake lock" time, but that's not because the cpu is working, its because the system is waiting for a response from the server after it has requested data. That "wait" uses effectively zero cpu, its just an I/O block on the background thread while the background thread must operate within a "wake lock" otherwise the Android OS could kill the background and you won't get your alerts.