One important point to remember:
Though the fact, that the previous Standby database became the primary afterwards applies to both variants - there are small differences which should for sure be considered. The most important is: After a FailOver there is no way to convert the former primary instance into a standby database for the new primary system: Due to the fact that both of them created redo information after the FailOver, they are completely out of sync, and in no way they can be synchronized again . The only possibility to get a new standby system again is to create it from the scratch.
After a SwitchOver, on the other hand, we have both, the primary and the standby system, available again as we had before. This means you should think twice before doing a FailOver.