Customize the title field
Views module comes with the field Has new content that outputs New or Updated depending on the status of the node as being viewed by a visitor. 

Anonymous visitors don't see anything because there is no history record about that users visits to a particular node. 

Authenticated users will see the word New if they never visited that node. If they have visited that node in the past, but the node has been updated in the meantime, they will see Updated. Once they visit the node again, they won't see any output for that field. 

So this doesn't work quite as you described in your question, but it still may be what you're after. 

You can add that field to your Views, Exclude it from display, and then Rewrite the Title field to include it before the actual title text.  

The way you've written your condition in the screenshot is criss-crossed, you're trying to output "updated" for nodes that are new (at least according to your logic of those times being equal). 

Your rewrite would also always show output for all nodes, even the ones the visitor has seen. Visitors usually don't expect that to behave like that. That's why it makes more sense to use Has new content field, but it all depends on your project and your visitors' expectations. 

The created and updated time always differ because the created time is the one when the Create node form was loaded in the browser, and the updated time is the actual time when the Save button was hit, when the node was actually saved. The difference in created and updated times is the time it takes to fill in the form ;)