RDB advantages
RDB is a very compact single-file point-in-time representation of your Redis data. RDB files are perfect for backups. For instance you may want to archive your RDB files every hour for the latest 24 hours, and to save an RDB snapshot every day for 30 days. This allows you to easily restore different versions of the data set in case of disasters.
RDB disadvantages
RDB is NOT good if you need to minimize the chance of data loss in case Redis stops working (for example after a power outage). You can configure different save points where an RDB is produced (for instance after at least five minutes and 100 writes against the data set, you can have multiple save points). However you'll usually create an RDB snapshot every five minutes or more, so in case of Redis stopping working without a correct shutdown for any reason you should be prepared to lose the latest minutes of data.
Earlier it was mentioned that rdb regular backups are a pro, but among the cons it was noted that it is not as good as aof, why is that?
Comment From: ptjm
The point about RDB is that the files tend to be pretty small, so it's cheap to archive them. AOF would never be described as small, but it has the advantage that it gets written out with every update. If the redis process crashes, the AOF will have all the data. RDB is written periodically, so a crash will result in some loss of data assuming there are frequent updates to the db. Note, I'm referring to a crash of the redis process, not the machine on which it's running.
It's possible to configure AOF (and it's the default) such that, if the machine crashes, you'll still lose data, but you can also configure it so that you won't. There's a performance cost to this, though.