PostgreSQL 9.2 EBS Snapshot on AWS
Yes, that advice remains valid.

A low level snapshot of a volume that does atomic snapshots is much like a plug-pull or server crash. When restored from the snapshot, PostgreSQL just does normal recovery where it replays the transaction logs.

It's a perfectly sensible way to take a backup, though I recommend also taking periodic dumps. Snapshot backups won't help you in the face of undetected filesystem corruption etc.